You don’t need a zillion watts, unless you want to listen to music very loud. 50 Watts would be more than appropriate. You will find that the less watts, the better quality amplifier you’ll get for your money.
If you just want to start, go to shopgoodwill.com. For $10 you can buy a decent receiver or for a $100, you can buy nice vintage amps. (Newer amps may cost $2-300) They will be a perfect start, and you can flip the vintage amp and not lose money and buy a more serious amp later. The brands I have heard and trust and are reasonably priced: Rotel, NAD, Cambridge Audio, older Denons, Yamaha, Marantz, Musical Fidelity. Most of these are not the audiophile brands that people appreciate here (I am not an audiophile with my tiny budget) but they are good to start and not break the bank.
There is a lot of used adcom, Parasound, hafler amps as well out there, they are fantastic quality for under $500, if you enjoy the search, keep your eyes on these marketplaces.
My number #1 rule when I buy cheap used stuff: what can I do with it when I no longer need it, do I mind if I am stuck with it...
Btw you have fantastic, quality speakers.