Nope most riders run singlespeed, and most use the same ratio depending on setup. I believe for a 22t front chainring (assuming thats what you've got) you'd be best with an 18t rear cog, you could get a singlespeed kit, which consists of a bunch of spacer rings for the rear cassette, a single 18t cog and a chain tensioner.
Or if you're planning on upgrading your rear wheel/hub in the near future I'd hold on and just get a fixed rear hub, new cranks, bashring, front freewheel, rear cog and tensioner then.
How tight is your chain at the moment as that could be making the gears slip a bit?!