Nothing wrong with PayPal itself. Plenty of big companies using it and it’s one of the most secure out there. But I’d suggest getting someone to integrate it into your cart.
Generally, with the smaller eCommerce sites do, is send the customer off to PayPal (or whatever payment solution they’re using), where they make payment securely, and any relevant order info is sent back to your site.
There are simpler ways of doing it, if you want to be really primitive about it, but I do think your idea of the way it will work would put me off. I wouldn’t want to go through all that hassle. Unless it was a hard to come by product that I was prepared to labour over.