There are a lot of good and cheap choices if a slightly longer filter will fit. I'm running a NAPA ProFormer 21348 which was under $5 rather than overpaying for a tiny filter from Briggs & Stratton or an OPE specific filter from FRAM, Wix, etc.
The O'Reilly equivalent would be MGL51348. As others said, the FRAM PH3614 or SuperTech ST3614 will also work as long as you have clearance. Anything that cross references to these should be fine.