Need a redirect URL for sending TO Paypal

[kingsj]

I am putting together a website for my boss with a shopping cart.  Currently, we are using Gravity Forms which allows us to redirect to paypal and send their "selections" along as a query string so that we can take payment through paypal.  I'm not deep into coding or development, but I do know that ALL I need to complete this function is the url to redirect to.  Any help??  Every url I try just sends me to the homepage of paypal.  

I've put 10 hours into this and am still completely lost.  

Thanks!!!

[PayPal_RobG]

The very minimum URL is: https://www.paypal.com/cgi-bin/webscr?cmd=_xclick&business=YOURPAYPALEMAIL

Note: if you use <form> tags, the "action"  needs to be set to https://www.paypal.com/cgi-bin/webscr and you can use a hidden input tag for the 'cmd'  and 'business' variables (e.g. <input type="hidden" name="cmd" value="_xclick">)