Is it possible to specify different prices for products in Store depending on the member group logged in.
For example, on our EE/Store site (currently only selling Retail) our client wants now to sell to Trade and Retail requiring two different prices. We could specify two inventories but obviously these would then cause problems as we would have multiple products with the same SKU.
It is not something that is built into Store at the moment but there are 2 ways that you can implement the functionality depending on the complexity of your product data.
If your products are fairly simple and wont have modifiers effecting the price you can create the different price levels as modifiers per product then use a conditional in your template to preselect the proper modifier in a hidden field. The only downside to this is that the product modifier names would need to be the same so the in template conditionals worked without any problems.
The second option would be to create 2 channels for your products. Lets call the first channel "product_details" which would house all of your details about the product but would not contain a Store fieldtype. In the second channel lets call it "product_prices" you would want to create 3 fields a Store fieldtype, Playa, and a dropdown or select field that would allow you select which member group the entry would apply to. Then in your template you would list the items on the site using the product_details channel and would then need to have the playa field search for the related entries where you dropdown or select had a value of the currently logged in member.
Lastly if you are experienced with PHP you could easily write an extension that would be able to handle this. If you were to write an extension you would want to use the store_process_product_tax hook to modify the product based upon the users member group before it is presented to the user.