Typically, angel money is a bridge loan to your A-round. So, no real equity is given up until you do your first round. The benefit of this is that you don't have to set a price, which is not good given you really have not built anything yet.
You also usually give a 10-20% warrant kicker for the angels taking the risk.
This equity is going to be potentially expensive - meaning you'd have to give up more equity for less money - so you'll want to minimize that risk by taking on "convertible debt" rather than pure equity.
There's also no real "going rate" for equity - it's a function of the opportunity, the team, the space, and what kind of traction you've already shown. An experienced team in a great market that already has paying customers may get $500k for 10% while an inexperienced group in a somewhat desirable market with little traction may have to give up 30+% just to get $100k. It's all relative.