I wanted something like that- guys can go up 5lbs no problem, but for me and the smaller amount i'm benching, 5lbs can be a lot when i'm going for more reps.
I went to a sporting goods store and got wrist weights. they are adjustable- inside them are tiny little metal rods that when filled, make the whole thing weigh 2lbs.
If i want to add 2, i wrap one around the middle of the bar, or i'll remove half the rods and put one on each end.