Depends on your hairstyle, but I used to have my hair cut about once a month for $20-25. I bought a set of electric hair clippers for about $30 more than 15 years ago and learned to cut it myself and have saved thousands of dollars. Its a simple men's cut, so it works for me.

An electric razor or a quality safety razor are also possibilities. I used to use the disposable gillette razor cartridges at about $4 per head, which lasted 3-4 weeks (I used them until they hurt to save money). Now I have both a safety razor and an electric razor (I don't need both, the electric was a gift). The safety razor was $45 and and blades are about $0.10. Blades last about a week instead of a month, but it paid for itself in about a year. I experimented with various shaving creams as well, but eventually went back to canned shaving cream because the time spent creating a good lather in alternative forms was annoying and not worth the savings.

The electric razor may or may not pay for itself depending on how much it cost and how often you have to change the head and the cost of cleaning solutions, but I do enjoy having it for a quick shave. It definitely is not as good of a shave though.