First, let us say that you should always talk to a tax professional about your particular situation. We’re discussing generalities here. Your particular situation may be different. Ok, we’ve made our lawyers happy with that disclaimer. Second, this discussion is only about U.S. accounting and income tax issues.
Cost basis is the amount you "paid" for something - your cost. If you bought our stock for cash, your cost basis is what you paid. If you received our stock because you shopped, or received it because it was a bonus, the IRS still thinks you "paid" for your stock.
When you get a share of our stock, we assign it a price. That price is what we're currently offering it at (you can see that on the bottom of every page). That price is your cost basis.