Integrating Shopping Cart on My site

> I need to get a reliable cart integrated on my website. > > I have spent a good deal of money lately and people keep leaving my site > unfinished and makeing off with the money. > > I will be contacting several certified developers on paypal to get a price. > > My site is [login to view URL] > > I currently have and API signature set up, but I really need an API > certificate instead, becaus eI have started a couple other sites and they > need the certificate and not the signature. > > I am looking to make it so I can accpet the following forms of payment. > > Credit Card > Paypal > Check/ Money Order > Possibly Google Checkout. > > My cart is currently a custom cart that my last webmaster created and it do > not seem to always work(I have no idea why) > > I need to get a reliable cart working and for it to still work with the sing builder on my site. They must be able to create the signs the same way they can now and see all the signs they have created on the cart page MOST IMPORTANT, THE SITE MUIST BE SECURE, AND USE A CART THAT WORKS WITH THE PAYPAL PAYMENT PRO > > > Can you help? > > Jay Williams