You can try searching against Reddit through Google. Perhaps take a look at blind. Sign-on bonus amount will vary a little from person to person unless it's clearly outlined in a job listing. It becomes a little muddled if you were poached by an internal headhunter from another company.

Two types of SOBs you'll get are lump to semi-lump payments during your initial employment or split fees over the set time period in your paperwork. For lump sums you'll need to pay back a prorated amount if you bail on the company before the term limit ends. The other splits it over a time period.

You can negotiate your SOB if you want to. While you can leave the company after your term ends, it kind of leaves a bad taste in people's mouths. Terms and conditions will vary.

The best advice I can give you is never touch that money until you clear your term and then stay a bit longer.