Nintendo’s running a big sale. One of the offerings is Starlink (Digital Deluxe) for just $20. Other notables include:
the various Sega Ages offerings at under $5.
Doom Slayers Collection for $20 (includes Doom, Doom 2, Doom 3, Doom 64 and Doom 2016). Doom 93 alone is $2
Entries in Resident Evil for $10 a pop
Most Lego entries are $20 and under, many skirting under $10
Metro 2033 for just $2.50! Last Light can be had for $5. Both are EXTREMELY well regarded games with astonishing ports to the Switch. A FPS cut to 30 and some lower quality textures are about the extent of the compromises, and the game features full 5.1 audio support. While not on sale, Alien Isolation is available for $20 (with all DLC), and is widely regarded as an amazing port that more than holds it own against even the mighty PS4’s version.
Civ 6 and Cities Skylines for $10 (or less) each
NIS’s old school-style action platformer Prinny series has both entries for $10.
Be sure to check for bundles! There are several bundles available that are a far better value than buying multiple titles separately. Of note is the Bioshock collection, which is $10, while each entry on their own is $8. The Diablo Collection, which is $30 and includes D2 and D3. Diablo 3 is available by itself for $30.
And hundreds more. Probably worth checking out, sale runs to around 9/25.