Hey are you looking for a solution like M2EPro with lets you integrate Magento directly with Amazon or eBay?
Other than that you could use something like Rapidflow to schedule CSV imports of stock status if you can export these from the other platforms.
Other than that it would be good to elaborate your requirements a bit further.
Thanks for the reply. Ill try to clarify.
Our Magento website sells 99% of our product, own brand and branded
Our ebay store sells branded product and clearance items and 1% of items not listed elsewhere
Our Etsy store sells only our own designed product.
All inventory is listed in an excel spread sheet.
So in summary Inventory is listed as such.
Magento and ebay
Magento and etsy
ebay items are not listed on Etsy and vice a versa.
So when we sell something on Magento, We have to manually update excel and the other platform its listed on.
And if we sell on Etsy we have to update the excel spreadsheet and magento.
As we grow it now takes as long to update everything as it is to pick and pack the items, We are a 1 man operation dispatch anything from 1 item a day in summer to 30 items a day in the run upto Christmas.
I'm looking for something that will make the Inventory management easier and cross platform inventory updates automatic but keeping the inventory on each platform as per the comments earlier.
Hope this clarifies.
If you're looking for a solution to avoid manual updates between platforms try sellbery. Once Amazon order is placed it's synchronized with your Magento store. For 500 items it will be cheap, and also you can start with 45 days free trial.