A pair or two of these will allow you to get going on Olympic-style weightlifting: snatches and clean and jerks, even when you make them, are basically dropped from arms' length overhead, so you need plates that absorb the impact when they hit the platform. Designed to be used for the Olympic lifts, they can be dropped on just about any surface without damaging the floor, the plates, or the bar.
With these plates, you can save money because they are cheaper than true bumper plates and you are spared the expense of building a lifting platform. Plus, if you put a pair or two on the bar, you can add some metal plates for your additional weight (whereas, when you use true bumper plates, as much of the weight as possible must come from bumpers, so that you have the maximum number of plates to absorb the impact when the bar is dropped).
Given the metal plates you have, you might need only a pair of 10s and a pair of 20s, for example, or a pair of 15s and a pair of 25s. These rubber composition discs are probably the best way to go for high schools, gyms, etc. that want to give the Olympic lifts a try. Excellent value.
Discs have a reinforced 2-inch steel center sleeve and can be used with any Olympic bar; made with pulverized rubber combined with a polymer adhesive which is then molded using a high-intensity heat compression technique.
1219-20 York 20-kg Rubber Composition Disc $88.00 each + S&H - please contact IronMind for a quote