If you're just doing simple transactions, then you could look at using the PayPal API

Thanks for your reply but i like to know that are we bound to use some payment gate way
cant we do it our self if not then is there any free payment gate way expecting reply pls

If you want to do it your self, as far as I know, you will need an audit (anyone who comes into contact with card numbers)

These, I believe, are quarterly and cost a substantial amount.

Unless you are going to be processing 1000's of transactions you are better of with a PSP (payment Service Provider)

I personally use Protx (Approx £20 per month). This works out one of the cheapest ways to take on-line payment.

I've heard PayPal is good now, but I've never integrated it so can't comment.

There are no free payment gateways or free merchant accounts. How you actually process a credit card will vary as each payment gateway and third party processor uses a different API. No audit or anything like that needed.

And it's not true that you need to process thousands of transactions for a true merchant account to be worthwhile. There are many factors that influence which is better for a business. You need to weight your options before choosing a provider.

I wasn't suggesting that a true merchant account wasn't worthwile, just that I have been informed that to process credit card numbers on your own site you have to have an audit, using a PSP you don't need to have an audit as the PSP is processing the credit card number for you.

With Protx you still need a merchant account with your bank.

Or is a 'true' merchant account different?

For a true merchant account a credit check will be done but that's not a big deal. Considering the benefits of a true merchant account over a third party processor, under most circumstances, it is usually well worth doing.

I use PayPal and it works great!