First off, how I bought it really has nothing to do with how I price it. Don't let the fact that you paid $11 for a domain and someone offers you 100x entice you on a rate of return level when you could get 500x or 1000x. And on the flip side, if you overpaid for something and now you realize the domain isn't as useful or popular as you thought, don't let that sway you from accepting a smaller profit either.
I price it based on a variety of factors including popularity of the term, length, ease of spelling, memorability, comparative sales data, etc. Any comparative data I can find is useful.
And personally, unless its a junk domain you're trying to liquidate since you're not going to renew it, price everything at at least $2500 at the lowest end. Even the smallest business should be able to justify that much (IMO), if not, they probably shouldn't be in business. Try and get a down payment and let them make payments before you negotiate down on the price too, unless its just a small token 10% discount or something.
You want to sell to businesses, not hobbyists or for personal use. Think about all the expenses a business incurs, a domain name, their brand name, is arguably one of the most important aspects. Price it like that. Its just a one-time expense after all. Compare that to how expensive office rental is, vehicle leases, equipment leases such as servers, phone lines, internet, etc.
Shaw Business Internet plans are from $115 to $195 per month. That's $1380 to $2340 per year. Just for an internet connection. Their domain & brand should be worth MUCH more than that, no?
Those free valuations are entertaining to look at, but when I compare the GoDaddy valuation on my sold domains to the actual prices sold, they are way low. I find that the Graen.com or Saw.com valuations are more comparable to my actual sales. But even then, sometimes those are also way low.