Well you just need an address, can't you just install a wallet like Jaxx, generate addresses in multiple currencies and list them in your product listings?
That would work if you didn't sell many items so you could easy tell which payment was for which sale. The problem is if you're selling lots of $10 items and you're receiving lots of $10 payments to your wallet you wouldn't necessarily know which payment was for which sale.
What about Shopify or one of these plugins?
https://bitpay.com/bitcoin-for-ecommerceI don't know anything about them so I don't know if they're reliable.