I'm looking to integrate ERC-20 Token into my shop. Now I have a lot of products so I need automated system to keep track of payments. I did some reading and it looks like if I write smart contract to handle this I would need to prompt user two times (one for allowance and one for transfer) which is not great. I wonder what is the common practice of handling this issue ? I know that ERC-223 solves that problem but unfortunately most tokens are ERC-20.
Another solution is maybe to generate new address for each purchase, but then I would need to transfer ETH to each address in order to move tokens which could get very expensive.