The "-110" number you are reading is just a moneyline for that particular bet. Think of it as a rate of sorts. That is, for every $110 you bet, you will win $100. For every $22 you bet, you win $20, etc. Most sites' min bet is in the low-dollar amounts.
Also, I don't know of a site that charges a fee to sign up. In fact, most offer bonuses as a percentage of what you deposit.