Bought 3 doz cheap spring clamps from Walmart that I found to be next to useless. Wound up using small 1 1/2″ C-clamps left over from a couple of wood kayaks I built many years ago. The C-clamp were far superior.
Amazon: Wooster Brush R730-9 Tiz Foam Roller Cover, 1/8-Inch Nap, 2-Pack, 9-Inch $5.05 per pack.
Home Depot: 2″ capacity spring clamps 99 cents each. Cheap and good; pick through the box to get decent jaw alignment and even spring tension.
Harbor Freight: Boxes of 3 dozen chip brushes for less than a dozen would cost anywhere else (even cheaper if you use a 20% off coupon from one of their ads in home fix-it, car, weekly throw-away, etc., magazines). Also nitrile gloves in sizes (better fit than “one size fits most” exam gloves).