Supported eCommerce platforms for website integration include the following options.
Many support two-way integration where items in RMS are synched to your website and orders placed online can be imported into POS for processing.
www.smartetailing.com (one-way integrator only; US bicycle stores are primary customer)
www.nitrosell.com (now known as websell)
www.kosmoscentral.com/ecommerce/rms-integration (X-Cart, Magento and others)
www.shopify.com (requires RMSify from their app store)
www.24sevencommerce.com (multiple cart systems and links supported)
Also appears to operate as: https://www.omnichannelcommerce.biz/rms-ecommerce-integration/
Costs vary based on features desired, startup fees, cart size (number of items), and monthly hosting charges.
Platforms that provide two-way integration include an add-in for POS to import cart orders for processing in POS. Some platforms also include tools for expanding product groups, adding extended descriptions, multiple photos per item, and more.
The more sophisticated systems provide a wide list of features designed for businesses that do a substantial percentage of online sales. You will need to weigh the startup and monthly costs against the volume of online sales you reasonably expect to do. Operating an online business can be as much work as opening a new store location.