What is the least expensive, yet decent 2 3/4 12 ga slug  and 2 3/4 buck for indoor target practice, for a pump?

I have not had a problem with the Rio buckshot.

Have also used rio with no issues, never indoors though.

http://www.gunbot.net/ammo/shotgun/12ga/buckshot/

 

http://www.gunbot.net/ammo/shotgun/12ga/slug/

Centurion makes good cheap slugs

I just got several boxes of Rio "reduced recoil" 00 buck at the Valley Forge show...I kinda like it.  Not too hard on the shoulder, and patterned fine thru a modified choke at 50 yards.  I'd like to get more.

Forgot to post.  AIM surplus has a bunch of RIO cheap

http://www.aimsurplus.com/product.aspx?item=ARIOBLR129&name=RIO+Royal+12ga+00+Buck+(Low+Recoil)+2+3%2f4%22+5rd+Box&groupid=17&utm_source=AIM+Surplus+Main+List&utm_campaign=e2537f581f-09272013&utm_medium=email&utm_term=0_6870497a6a-e2537f581f-18710745

Rio is great.. i bought a 1000 rounds about 2 years ago for my 870 and never had an issue. Even both my s12s like them. All i have left now is 1 1/2 cabelas cans full better get more !!

Forgot to post. AIM surplus has a bunch of RIO cheap

http://www.aimsurplus.com/product.aspx?item=ARIOBLR129&name=RIO+Royal+12ga+00+Buck+(Low+Recoil)+2+3%2f4%22+5rd+Box&groupid=17&utm_source=AIM+Surplus+Main+List&utm_campaign=e2537f581f-09272013&utm_medium=email&utm_term=0_6870497a6a-e2537f581f-18710745

That's where I ordered mine from last year. I got 500 rounds of buck for $230 shipped. It's more expensive now, but still a good price.

Tried the Rio, works great