The more blades the better, but they are expensive. Also, cheap razors blow goats. They are harsh and can tear up your face. They should also be disposed of promptly because you are just begging for a staph infection. Trust me, you don't want that.
The most cost-effective thing to do is invest in a high-quality electric shaver and maintain it properly. I found the Panasonic ES8109 wet/dry was the probably the best one out there. In a few months, you will find you have spent less than you would have on blades.
Anyway, if it eats your face, chuck it. Don't share and always dispose of promptly, if you want to reuse, you might want to consider a disinfectant. Use a very slippery cream, not water. Believe me, if there's anyone who knows about shaving, it's a MTF!