Most of these websites provide very small amount of bitcoin. so they are not useful to test large number of transactions,
That faucet I linked you to provides 0.089 per request (and currently has 8.something). I'm sure you can turn up another one or two of these testnet faucets pretty easily. If you have 0.2-0.3 testnet coins, surely that's enough to test a large number of transactions. For one thing, is there some reason why you don't control the receiving addresses? If not, you just send coins back and forth as you're testing whatever you're testing. Even if you can't recover them, at 0.3 testnet BTC you'll have 30000000 satoshis to play with.
Surely this is enough. Anyway, I don't resent you posting here to look for testnet coins, I'm just saying how I got them when I needed them and what I did with them when I was done.