The dot scopes in my opinion are too coarse/large for target.
Something with a nice fine reticle or target dot will be a good choice.
Don't be afraid of magnification, even @ 100 yards it is nice to have high magnification, which also eliminates the need for a spotting scope.
You could go fixed or variable power but remember that some scopes have varying eye relief and some are constant.
Sightrons are a good choice and have nice reticle choices. I am on my third one, I have a 6.5-20x50 on a 17HMR and it never comes off 20X.Vortex also have a few options, Zeiss have nice glass but you are limited in reticle options, I am also on my 3rd Zeiss Conquest and I very much like the optics and clarity and fine mil-dot reticle.
All of these and a few others will be within your budget.