I am building a new AR-15 and want to get a red dot sight for it but need to stay cheap. I have two other AR's with EXPS2-0 with G33.STS Magnifiers on them and really like them a lot. I'm looking for something under say $150 that will do the job. This will just be a backup and target shooting for fun gun and of course if I need to can always swap out the Eotechs from the other two. Any advise on what would be a good cheap red dot to get?