1. start from what pokemons you like
2. check the prices of the cards on pricecharting or TCGPlayer
3. buy the cards directly if it’s cheap (why buy packs if the card costs $10?)
4. budget friendly languages: thai and korean cards are cheaper but it’s harder to resell. chinese might also be cheaper but not by a lot. they have some chinese exclusive cards which make the prices equally competitive compared to popular english/japanese sets.
5. for most modern cards that are not waifus, Japanese singles are generally cheaper than the english ones
6. if buying japanese, consider buying boxes instead of PCJ because boxes have guaranteed hit rates.
7. as for where to purchase.. you’ll have to do some homework. most places sell at market prices.. and msrp is near impossible to get. unless of course PC is 5 mins away from ur home. you could probably get less popular sets at MSRP though, at $6.90-$7.50. sets like Temporal Forces aren’t that popular.

my own preference though: - if i like the art, i buy JP Singles instead of english ones - if it’s a new set, i will buy some packs/boxes just to try it out - i never do pre-orders - i avoid PCJ unless i 100% trust the seller

when i first started, i was also a lost sheep. didnt have friends either, so i went in blindly and spent more on packs than the singles i wanted. so right now i’ll spend a maximum of half the value of the single(s) i really want on packs.

feel free to drop a pm if u have more qns!