>>6969531Research the figures you want and in which sets they are, sometimes the sets are cheaper when some of the rarer figs are sold for 10$.
I also second Aliexpress bootlegos if you aren't autistic about them needing to be real Lego. 70 to 90 cents per figure, the chinese make more costume variants so you have a wider range of options than Lego. For example, I hate all official Captain Americas but the chinese have some versions with a mask piece that makes him look more complete, all Caps I display are bootlegos. Especially big figs like Hulk and Thanos are practically identical or superior (removable hair and head swivel) while Legos big figs cost 10-20$ alone, 30-40 if you are unlucky enough.
Really hope you have the willpower to keep the collection small, I sure don't have it but I can imagine a small figure collection like you described looking extremely tasteful unlike Funko Pops.