Hi Rose,
Please check out my earlier thread on this below:
https://www.etsy.com/teams/10366/bitcoin/discuss/18115727That refers primarily to Blockonomics.co as a way to generate professional, hosted invoices for your customers, but you can also use many wallets including Coinbase, Blockchain, and Airbitz to generate payment requests for your customers. The main difference (besides not being hosted) is that wallet payment requests will calculate the equivalent bitcoin amount when you create the payment request. Blockonomics, on the other hand, will continuously update the requested bitcoin amount to stay current with the market at the time the customer actually pays.