Just about anything will work at 100 yards, even a rifle scope mounted to a block of wood and clamped to the bench.
.22 holes in a black bullseye are very hard to see at 200 yards with any spotting scope, unless the light is just right. One method that helps - lay a white sheet on the ground in front of the target to reflect light onto the target face. Some folks have put a white board hung at an angle on the back of the target board in an attempt to reflect light back through the bullet holes - sometimes it works.
.30 caliber holes are fairly easy to spot at 200 yards in black bullseyes unless the sky gets too dark.
If I am shooting with a scope at 200 or 300 yards I use targets with low contrast aiming points; either store bought with orange, or targets I designed on the computer with blue, orange, or turquoise aiming points. Low contrast targets with small aiming points allow .22 bullets to be seen easily at 300 yards since the target is mostly white. Low contrast targets of about any size are useless with iron sights beyond 100 yards, and they pretty well suck at 100.
For a budget scope, check out the 60 mm scope Champion's Choice sells for $210. Eyepieces are available from 22X to 60X for $50. They don't have a web site, call 615-793-4066 to ask for a catalog.
If you buy a 60mm Kowa, you will probably be very happy - the buyers remorse won't last long, especially if you take a look through someone else's scope after you get yours.
If you wear glasses do yourself a favor and get a scope with a long eye relief eyepiece, one that specs at about an inch. The only eyepiece I have ever looked through that is truly LER is the Kowa. I owned a Bushnell Spacemaster with variable magnification eyepiece that was advertised as LER, but it's not by a long stretch. The look through variables is too compromised to add LER.
Jim Owens' prices are as good as any, and his service is first class. Occasionally he has used scopes.