as a "private amateur" angel investor, i put ~$300K into 13 deals over a period of 4 years ('04-'84(, at a median size of around $20K. my largest investment was $100K; my smallest was $5K. most of them were at valuations south of $3M (in a few cases i did A rounds north of $5M pre, however in both cases i was working or consulting with the company). so far it looks like 3 of the 13 will do >5x, another 2-3 are likely going to return 0, and the other 5-6 are still tbd. i'm hopefuly i'll end up with 3-5 wins, and an aggregate return of 4-5x over a period of perhaps 7 years.

as a "professional" angel investor now for a VC fund, i typically invest $50-$250K at valuations between $1-3M pre-money (however i'm new on the professional side; only done 4 deals since December). too early to say on either wins or returns, but i'm happy with the deals i've done so far.

i think most private angel investors (in Silicon Valley) who dabble do deals at between $10K-25K. most professional angel investors in Silicon Valley who do it as their primary profession invest between $25K-250K per deal.

your mileage may vary.

some angels may do deals as high as $500K - $2M, however those are select cases. most times there are multiple angels syndicating.

sorry that should be "over a period of 4 years ('04-'08)"

FYI, in the first 2 hours you can edit your posts via the direct link to make corrections like that. (And thanks for the great specifics in the grandparent post.)

I'm not sure you'd be doing the startup a favor by throwing a lot of money at it in early stages. It might actually be better (for the startup, maybe not for the investor) to invest 80% of the amount the founders want to raise, just to force them to stay resourceful and frugal