Need help!

OK guys and gals, I need some help here. I shot bullseye in my younger days, my last match was in 1970. Now for some silly reason I want to get into it again. Back then scopes or any optical sights were just beginning to show up. I always shot with iron sights. Now I see Red dots and all sorts of optical sights. My club has a fall league coming up in September, 50 ft indoor that I would like to try. I have a Ruger Mark III that has the Valquartson upgrade kit, so my question is what is a good sight to try for an old beginner. I'd like to keep the budget low but I don't want junk.
whats the opinion on Optical Planet? They seem to have good prices. I know at my age I won't break any records just want to have some fun.

Ultra dot matchdot

Lot of people shoot Ultra Dots.  Some of those people are reporting serious negative magnification issues.  (See thread in this section titled Sightron Red Dot)  Also go to the Encyclopedia of Bullseye and read the article on shooting with red dots by Brian Zins.

Optics planet is great.  Not as fast as Midway, but fast enough.  Ultradot is great for the price.   I like the Matchdot because I'm not sure what size dot I like.  I'm working through that now.  My eyesight is better at the gun than at the target so I'm focusing on the dot not the black.  Not sure if that's the best idea or not but I gotta start somewhere.

I don't think you can beat the plain ole one inch Ultra-dot for the price. Some of mine are classics, dating back to the 1980's. That's pretty good service...Jim

I tried a red dot and couldn't use it because I have astigmatism in my eyes and only see a fuzzy dot with little squiggles coming from it.

I like the matchdot 2 because it is easy to tell if I am zeroed at 50 or 25.   I also like the different dots which help when moving indoors to outdoors.

primary arms sells a great micro dot for under 90.00 bucks that would work great on that gun. looks like and has the same mount as the aimpoint micro. Optics planet has it on sale for 11% off of 89.99 that's just 80.00 bucks

http://shop.opticsplanet.com/primary-arms-primary-arms-micro-dot-with-removable-base.html?_iv_code=29R-RD-MD-RBGII&utm_source=google&utm_medium=cpc&utm_campaign=plusbox-beta&gclid=CO_q0_Tv8M4CFdgPgQodhdEGtw