Don't go near 1st edition booster packs. They sell for $200+ dollars and The base set has an effload of trainer rares. so not worth risking it because only Charizard and Blastoise in 1st edition would gain any sort of profit. Venusaur may break even.
The best way to collect 1st edition cards is to buy them individually. You could buy 10 booster packs valued at over $2000 and still not get the Charizard which is worth $500-800 dollars. So if you were willing to spend $200 every time on a pack just save up and buy the card as an individual. If you wait long enough and you keep the card in faultless condition to how you bought it, You will see a profit out of it but it's alot of money to fork out as a collecting purpose that may turn "investment" down the track.
Shadowless are worth only $50 and they are the same dull colour to them as the 1st edition packs are, just without the stamp but the price is much more reasonable. I've bought 4 packs i believe and I got a Zapdos holographic out of it. For collecting purposes you will probably lose out but if your heart is in it then never question the $ value of what you want. as long as it doesn't break your bank and it's spare money but that's my advice on shadowless, 1st edition you'd be stupid to go for them unless you had the intention to not open the pack and let it collect dust for a while in a container.
Don't waste your time with 1st edition Jungle or Fossil's Unless of course they are only around $1 dearer. The inflation between the unlimited to the 1st edition is barely anything. The most valued card out of both combined is a Dragonite in first edition and will fetch $40 at top dollar. You may go as good as doubling your money in comparison to a unlimited pack but generally it wouldn't double in value and if your buying packs in bulk you see a difference so know I only buy unlimited Jungle and Fossil unless the value is there.
If you are looking at Shadowless. Buy the theme decks in Shadowless. they range from 70-90 dollars but you get 60 cards and a holo is guaranteed. That will exhaust your options in terms of getting shadowless cards for better value. You could by three booster packs for around $150 bucks and not get a holo. I don't think it's unreasonable to go for these packs because I've done it before and I haven't regretted it when i didn't get a holographic but my eyes lit up when i pulled the Zapdos.
The best value I could give you is a Jungle Booster box in Unlimited. They are around $180-200 dollars. The Fossil box in unlimited is dearer again but still reasonable value. DO NOT shoot for 1st edition in either of those expansions they can range anywhere upwards of $120.00 dearer and the value doesn't really warrant paying the extra. If a 1st ed box comes up for around $50 dearer then the cheapest unlimited box you can find then i'd nearly say go for it.
The 1st edition packs in these are a waste of time and I personally am not a fan. They are also seen as not true "1st edition" cards despite having the stamp because of the shadowed borders. Only 1st edition base set and the 2nd run of the base set without the stamp are shadowless cards. Be aware of the Machamp in the base set that it only comes in 1st edition form and is shadowed, This card is worth next to nothing.
My approval list:
Unlimited Base Set Booster Pack (Range from $12-16)
Unlimited Jungle Booster Packs (Range from $6-8)
Unlimited Fossil Booster Packs (Range from $7-9)
Shadowless Base Set Booster Pack (Approximately $50.00)
ANY OTHER BOOSTER PACK THROUGH TO NEO DISCOVERY SERIES.
Shadowless theme decks (Range from $70-90) Guaranteed Holo (IF you were interested in purchase shadowless booster packs, exhaust this option first. Then if you decide against going shadowless then you will have something to show for it and you could re-sell and get a unlimited version of that card and you will get some money back).
Unlimited Fossil & Jungle Booster Boxes (Range from $180 (Jungle)-$240 (Fossil)
As for the base set booster box. Cheapest you can buy one is around $450.00 and my tip is. IF you were willing to pay that much, then look out for a green winged Charizard on one side of the box. If it's green winged and the wrapping is clear without no logo's then there is a very good chance of the box being shadowless. These boxes cost upwards of $600ish bucks but if you bought them seperately then re-sold them, You'd triple your money. I am not a fan of selling even if that opportunity came up because Shadowless cards are very rare and if you sold what you had you will have limited opportunities to re-purchase and will get less chance to as time goes on.
Green Winged Charizard boxes with "Wizards of the Coast" wrapping is much less chance of being shadowless. They added the WOTC logo to the wrapping at a later date and no one can be sure that shadowless cards were still printing then so i would buy at your own risk then because there is no guarantee what so ever that the cards would be shadowless, Still a chance but it wouldn't be in your favour at all.
Blue winged boxes are strictly Unlimited and no chance of being anything other.
If you are only after collecting them and looking at the Art, another real possibility is go for boxes of different languages. If you do not play the game you don't really need to read the pokemon's move set. In Italian and Spanish Languages the name of the pokemon up top will be in standard english but everything else will be in the respective language.
You can pick up Italian, Spanish, French, German or whatever you find that isn't english for $200-300 dollars doesn't matter what box. Keep in mind that the 1st edition in those languages are shadowed but there is some possibility you could fetch a reasonable amount for 1st edition Charizard, Blastoise, or Venusaur that may nearly add up to the value of those of the shadowless print, It will almost certainly fall short but this is incredible value in comparison to your other options but if you want cards in 100% standard english then it will cost you some serious money, There are some cheap options but Base set altogether is a bit dear over time (Doesn't matter if it's Unlimited, Shadowless or 1st edition)
If you were looking at a base set box, I would hold out for a little bit to see if a green winged box with clear wrapping goes on the market but putting it wisely. If you see a green winged (with WOTC wrapping) and a blue winged Charizard box for similar prices than (DEFINITELY) take a stab at the green box because it has a chance of being shadowless whilst the blue box will always be unlimited print.
I think that's about it. Sorry it was a bit long but I made a few rookie mistakes when i first collected them for the 2nd time around 6 months ago. I didn't really research before i bought and i lost out a bit in value but not too much.
Feel free to PM me if you have any other questions!.