Having a serviced application in the "cloud" does not remove the original issue (the original post above) where the shops and the on-line sites are out of sync.
The shop owner needs to maintain the retail sales/stock application, and the "cloud" copy.
This requires extra efforts, and unless automated, will always cause discrepancies.
If one runs a retail shop, he/she wants to focus on the core business, so needs expert help. One needs a day off every now and again to spend with the family, or god forbid, go sailing. (Not spending weekends and nights to set up the shop, and synchronise the on-line stock)

Setting up an eBay shop may be an option.
A business case needs to be set up to compare the up-front and ongoing costs vs. maintaining eBay shop.
Similar to what WestOzWind did above.
What I would pay attention to if I was running a retail shop, and wishing to expand do the on-line presence:
1. Get a young enthusiastic IT graduate on a full time basis. He/she can help with the shop application and on-line app.
2. Find a way to keep your stock database in sync with the on-line one. Never type into two.
3. Once (if) you commit to the hosted application, figure out how to transfer the shop to another host without losing the shop "front end".