>>7573832As somebody who said this exact thing years ago (during TransFormers Energon, circa 2004)...don't.
Toy collectors today are poorer than dirt. I cannot stress that enough. Marvel Legends is a great line that's worth the $20-$25 retail but there are alot of people out there that won't touch it for anywhere north of $10. For the popular characters. The weird bit characters, that are still great toys but really obscure, clear out at $5 if you're lucky.
Then there's marketplace problems. The fees are about 20% and people expect free shipping. Even at $40 on a $20 toy, the marketplace is making more than you.
40 - 6 (fees) - 7 (shipping) - 21 (item cost) = 6
47 - 7 (fees) - 7 (shipping) - 21 (item cost) = 12
Good fucking luck getting either for more than one or two figures each year. And, since you mentioned buying retail, don't count on being able to pick up $5K of hot figures unless you live in the sporting goods section of a decently stocked Walmart. Even if I wanted to scalp, I couldn't do it in volume. I'm lucky to find 1 or 2 good figures over a month hitting 4 or 5 stores.
Conventions are a little better for selling but, again, it's an issue of cost and timing. Cost, you can pay anywhere from $50 to $1000 for a table, which you pay regardless of performance. Selling joke wholesale, I never broke even unless than $1000 in sales and can count those shows on a clumsy shop teacher's hand. Good cons are few and far between, so there's always the risk that whatever you have will be old news by the time the next one rolls around.
That said, the bank idea is horseshit. Interest is a joke, even on CDs where you're locked into stupidly low rates. Outside of fire/burglary risk, money in the mattress is every bit as good as money in a bank account. Better off with a TDAmeritrade account if you want any sort of return.