I have a 2008 Buick la zerne looking for a battery tender to use,it's garage
kept,does not get run alot
I found a really nice simple one at WalMart for $10. It's still working great now after several years and the price is still $10. I like the long (12foot) heavy battery leads and the unit itself plugs into the wall socket or an extension cord. Premium quality Schumacher brand.
The $9.99 and the $19.00 ones at Walmart work well. I have 1 of each. Whatever you buy make sure it says for battery maintenance on the package. You do NOT want to use a trickle charger. A battery maintainer will shut off when the battery is fully charged and will turn back on when necessary to keep a full charge. A trickle charger will charge all the time which will eventually ruin your battery.