How big is your operation? Depending on size, requirements and budget you may well be better off picking a pre-existing hosted platform, like
Shopify, and if down the line you need third party involvement you can hire a company with Shopify experience, you'll save a lot of time and money that way.
(If you did hire a local company to
build an online store for you, it's probable that they would use Shopify and charge you a lot for the privilege, by going direct to Shopify you would cut out an expensive middleman, unless you have unique requirements that Shopify can't meet.)
(I'm a website developer and I would use Shopify
)