Pre-approvals and $4 will buy you a latte.
I've been rejected by every pre-approval I've applied for. Some of them are generated by your credit score range (for example, Capital One might periodically send out pre-approvals to everyone with a 550-600 fico).
Others, I learned to my chagrin, will send you pre-approvals based on what magazines you subscribe to. I subscribe to the Economist. They have my last name misspelled (**bleep**e instead of White). I receive a few offers from AMEX with this same misspelling.
Pre-approvals cost me about 7 inquiries with NO credit card approvals.