Alejandro Cabrera released a free Native Instruments Kontakt instrument of Foley footsteps. You launch the Kontakt player and then you select "indoors" or "outdoors" and then the type of shoes. Could you use a wider selection of each? Of course. But it's free. Is it worth paying for? Yes. Do you have to? No.
Signo makes a number of different Foley instruments for Kontakt too.
Note that you need the full version of Kontakt for these instruments to work for you (at least for more than about 15 minutes).
I haven't actually tried these in a post-production environment but it seems like you could really do a lot by "playing" your Foley on a keyboard. Frequently one is "playing" footsteps by "walking" with shoes in one's hands so it's not that far out a concept. It's certainly worth a try.
(Kontakt is a software "instrument" you play with a MIDI keyboard or similar.)