which AR 15 would you recommend for weekend plinking - nothing fancy or expensive---just good and reliable.  Some say Eagle Arms, others Bushmaster.

To me “Plinking” means recreational shooting: cans, old bottles, turtles at the pond and the like.  I’d get a Ruger 10/22 you can pick one up cheep, the ammo is cheep and magazines are cheep.  It’s a much simpler mechanism and is less prone to misfeeding than a low end AR-15.  Of course the 22LR is a lot less powerful than the .223 rem
If I can’t convince you to get a 10/22 spent about 650-750 for a good AR.  It’s less expensive in the long run because you won’t have to pay a gunsmith to fix your rifle.  

Well, I have an Oly Arms "Plinker" model, for only $570, and it shoots great!

The best "plinker", as far as center fire rifle that i have, is a marlin 9mm carbine.....cheaper to shoot than a 22mag, and almost the same thing as the 10-22......[:)]

I would also suggest a 10/22. I have a heavy barreled 10/22 and I love shooting it. Accurate and reliable. The ammo IS cheap but the mags are god awful expensive for anything over ten rounds.

A good inexpensive ar is a hard thing to find. I built one that works great but some seem to have problems w/ homebuilts. I like the Bushmasters from personal use.