Take a look at the Xantrex TrueCharge 10. They seem to go on eBay for $65 to $85. This is a 3 stage charger.
I have not used this particular model but I've used their 20 and 40 amp units with no problems for years. They are more sophisticated than the 10 amp units if you need features and/or the capacity. They are also available on the used market. Yes, going cheap on a charger is tempting but spending a bit more often is less expensive in the long run in terms of battery life and reliability.
