Thankyou everyone. This was first query here and now I know who to turn to when in doubt.
Could the problem be with tenses?
My try:There sure is tech savvy crowd among first lot of five hundred who bought <product> without causing big dent in their wallet.
There sure was the tech savvy crowd who were among the first 500 to buy the product without causing a big dent in their wallets.
There sure is the tech savvy crowd who will be among the first 500 to buy the product, without making a dent in their wallets.