I read that trying to run multi store on a shared server runs into issues if you are processing payments across multple domains because of the way that the SSL certificates are assigned to domains/ip addresses.
My question is....how can you get away with using multi store on a single shared domain? Are there secure payment modules you can use that dont require an SSL?
My goal here is to use the multi-store feature on my single core magento install, across different domains without having to spend the money on dedicated hosting.
Never attempt to go cheap on your hosting!
Try a VPS - You can get one of these for as low as £30 a month, you won't run into any issues with SSL's or multi-stores.
Also performance wise, I wouldn't suggest anything less than a VPS for a Multi-Store setup!