The "best" way into med device sales is to be a high performing B2B sales rep and find an entry level device role that requires a few years of B2B sales experience. If you're already doing that, there should be many positions on linkedin that you'd be qualified for with companies and you would be best of just applying directly to those.
There are some 3rd party recruiters online that do B2B or outside sales to device, but there aren't a ton. If you search around online you should find a few, but most 3rd party recruiters are only trying to get in touch with current device reps. You can't go wrong connecting with corporate recruiters at companies you want to work for, though.
MSC is expensive, unnecessary, and only prepares you for ortho sales which is just one area of device. Why would you pay for this when any company is just going to train you and pay you while they do it?
The average base that I see in device is 60-80k for reps so yes, most reps are making significantly more than 100k per year. It depends pretty heavily on what you're selling and where you're located. If you work for a company like Medline and sell disposables on contract you shouldn't expect to make as much as the guy pushing CT scanners for GE. Safe to say the average salary in device is between 150-200 but there are definitely people running around making 400