TG16 is cool but overhyped a bit. Bonk isn't better than Mario, Legendary Axe isn't better than Castlevania or Ninja Gaiden, Neutopia isn't better than Zelda. Good games, but not 'worth' 10x what NES/SNES counterparts are. Other 8-bit systems can't rival its shooters though. It's a B+ console with A+ pricing.
If price doesn't matter, go crazy. Spend $100+ on Rondo of Blood, Gate of Thunder, Air Zonk, Ys, Nexzr, etc. There are sick PCE games, they just tend to be very pricey. There are not many $9 SMB3s or TLOZs on TG16/PCE. I would not buy random cheap games, save your money for the good stuff.