>If you're trying to get complete sets just for the sake of having them, wait until they rotate out of format and buy them cheap
>late gen 2 and gen 3 cards are generally the most expensive, because there were a lot of very rare chase cards during that era and the initial fad was dead
>Skyride and Legendary Collection, in particular, are known for being notoriously shortprinted compared to other sets. (and the first RS set, but there weren't really any sought-after cards in it so nobody cares)
>gen 1 cards aren't worth shit unless they're a very early base printing, an unusual misprint (shit like the Wartortle that evolves from Wartortle, not common stuff like the Pokemon who have their HP70 instead of 70HP), or some variation of Charizard
>never buy single booster packs online, especially if they're cheap. They're always weighed. The only exception is blister packs, because the extra packaging throws the weight off
>don't expect to ever profit
>if you do want to profit, the only reasonable way to do it is to predict that a now useless card is going to be sought-after in the future meta and buy them up for pennies to resell. Uncommon trainer cards tend to have the highest inflation (sometimes jumping from less than a dollar to 10+), but also tend to get reprinted
