thoughts on resellers? i might be overreacting idk

i’m always kinda frazzled when i sell jackalopes for what i think is a reasonable price (this applies to when it’s someone i spoke with directly about buying them) and then i look on expo and lo and behold it’s there for practically twice the price they bought it for??? i don’t know, i know i shouldn’t be mad because people can do whatever they want with what they buy but man it just feels sort of scummy that i thought i was giving it to someone who genuinely Wanted it for a more accessible price but it was another rich reseller trying to make a profit. i just don’t get it?? if it was like a random listing from me they found on expo i wouldn’t care but it’s the fact that they agreed to/more often than not GAVE ME an Exact price. if you KNEW you were going to sell it for twice as much then why on earth did you give me a price that’s way cheaper? especially with all the times i’ve reinstated “i am very unfamiliar with worth” idk i can’t help but feel taken advantage of in a way. again i know it’s not a big deal and if you buy something it’s up to you what happens to it but MAN it just doesn’t feel good on the seller’s end especially since practically all the jacks i sell i pulled myself and everyone knows it takes so many coins to get something remotely good. and what about the people who really WANTED it? who could’ve bought it for that low price, and had something good they could actually afford ???? that’s why i don’t sell wishing coins for 750 anymore because it’s always rich people camping in my den and hogging everything for financial gain, leaving none for the jammers who can’t afford them at normal price. i know it’s a very inevitable thing but i can’t help but feel irked about it… both buyers and sellers are being taken advantage of in this instance no??? idk man