The first thing you need to check is if the bookmakers you are interested in actually offer odds feeds. It's usually done through their affiliate department as an acquisition tool, so if you don't bring any new customers for them they might cut off your access to the feeds.

If they don't have feeds it will be really expensive to get a tool that scrapes the websites themselves. It will also need to be updated by the developer as soon as they make any changes to the websites.