Do you already have the store website built? If so, supporting Bitcoin transaction can be easily done using the Stripe API (
https://stripe.com/bitcoin). I'd be happy to walk you through how to do it, if you'd like--I've used Stripe before and it's a reputable service. Unfortunately, there is a minor fee for each transaction processed.
A free alternative, just from Googling, is the Blockchain.info API (
https://blockchain.info/api). Although I haven't used this one, at first glance, it looks pretty legitimate.
I'd like to caution that whatever system you end up going with, make sure to be very safe with safeguarding any sensitive information that may get passed around.
As scout5 mentioned, specifying the technical stack that you're hoping for would also help the developers decide whether or not they're a good fit for the gig.