Generally, angel investors don't have a minimum (in terms of ownership interest) like VCs do. The reason VCs have a minimum ownership interest is that there's a maximum number of investments they can manage (sit on the board of), so they need a minimum ownership interest in order to "move the dial".
Angels, often have a range of investment amount they're comfortable with and if they're making similar types of early-stage investments, they may have a range in terms of company valuation. But, it's often a wide range. Could be anywhere from $250k valuation to $2MM+ valuation. It depends on the situation.
If your business is worth $1MM, then 1% for $10K would be about right. While you're putting sweat equity into the business, they're fronting dollars. They're going to want to get good value for their investment, that is, a portion of your business that's proportional to the value of their dollars against all other value in the business.
If all you have is an idea and a couple guys writing code, estimate about $50K per year per developer for sweat equity. That's what those dollars are buying.