Rib roast generally goes on deep sale around Easter. My MIL buys a bunch and deep freezes them. Not sure how safe it is to hang onto those suckers for months but it hasn't killed me yet.

A few thoughts:
Costco sells the whole rib rack that you could cut into 2 or 3 pieces and cook/freeze as you like. The whole thing is usually $80-$120 or so.
Whole foods sells a few cuts that roast nicely but vary in fat/deliciousness. The first is chuck flap which they also call chuck skirt but its not really a skirt steak but part of the chuck. Its fibrous and tapered like flank but fattier and fantastic. You must slice across the grain. The other steaks that are good roasted but are not quite as fatty are trip tip and sirloin. Something that is delicious but fatty is what they call boneless short ribs. This is simply another flap cut from the bottom of the chuck. Fantastic grilled or braised. I've had the best luck at the Glover Park WF for meat.

If your willing to use sous vide you can make cuts of meat like chuck medium rare. It takes 2 days, but it works.

Chuck or rump roast. Cut up some butter and put on top. Sprinkle liberally with salt. Add some pepper. Cook 2 hrs in low oven (300-325). Cut up a couple sweet onions and throw in pan. Cook for 2 more hours.

another article that will help you ID the roasts:

http://www.epicurious.com/ingredients/all-about-beef-roasts-from-chuck-to-rump-article

Oh, and by way -- top sirloin is usually cut into steaks, not roasts and is a more expensive cut. Cheaper than rib roast and tenderloin but not really "poor man's" prices.

Here is a chart that tells you the different cuts of beef and identifies the roasts:

http://stallingspolledherefords.com/images/2010/apr16/CutsOfBeef.jpg

We raise beef and I like the chuck roasts and the rump roast the best but the rump is a bit tougher and it perfect after a long day in a crock pot. If roasting I'd use a chuck roast but I still prefer those in the crockpot to get the meat falling apart and melty.

Anonymous wrote:

Anonymous wrote:Eye round?

Eye round can be good--if cooked PERFECTLY medium-rare (tricky to master, because if done wrong you're left with shoe leather). It's more like a london broil than a good roast beef.
The thing about good roast beef (such as rib roast), it's got just enough fat to make it tender and flavorful, and it really only needs salt, pepper, and one or two other things if you want...

I've had consistent success with this simple method:

Preheat oven to 500 degrees.
Coat eye of round with salt, pepper, and olive oil.
Roast for 5 minutes per pound. Then turn off the oven, leaving the door closed and the meat inside for the next 2 hours. Residual heat finishes the cooking.

But, yeah, it's not like a rib roast.

Anonymous wrote:Now, my fave is skirt steak in a crock pot. It falls apart and no prep required. But, needs to be a thicker cut like they sell at Latin market butchers as fajita meat. I buy a 2-pound piece whole. Put just adobo on it its dynamite. I pay maybe $15- $20 for 2 lbs.

Or, lamb shoulder chops in a crock pot. I do brown it for a few minutes each side in olive oil, then put in pot with little olive oil, worchestershire, garlic, and McCormicks Perfect Pinch Lemon Pepper. The shoulder is maybe $8/lb pretty cheap.

This is very helpful to the OP, who is asking for a substitute for rib roast. Skirt steak with adobo, and lamb shoulder? Thanks for sharing, though.

It's not nearly as good a rib roast but a sirloin tip make a nice roast beef. I don't see it often in the store but you can probably ask the butcher. Also, tri tip is good roasted.

Now, my fave is skirt steak in a crock pot. It falls apart and no prep required. But, needs to be a thicker cut like they sell at Latin market butchers as fajita meat. I buy a 2-pound piece whole. Put just adobo on it its dynamite. I pay maybe $15- $20 for 2 lbs.

Or, lamb shoulder chops in a crock pot. I do brown it for a few minutes each side in olive oil, then put in pot with little olive oil, worchestershire, garlic, and McCormicks Perfect Pinch Lemon Pepper. The shoulder is maybe $8/lb pretty cheap.

Rump roast? Or chuck roast.

Anonymous wrote:Eye round?

Eye round can be good--if cooked PERFECTLY medium-rare (tricky to master, because if done wrong you're left with shoe leather). It's more like a london broil than a good roast beef.
The thing about good roast beef (such as rib roast), it's got just enough fat to make it tender and flavorful, and it really only needs salt, pepper, and one or two other things if you want...

Eye round?

i LOVE rib roast (AKA prime rib), but I'll reserve it for special occasions: it's just too damn pricey for a regular old sunday dinners.
But when I do want to make a nice roast beef that is tender, beefy, and delicious--what's a less expensive runner-up to a rib roast?
I've read about top sirloin roasts, but I never see those in the market (unless it's sliced thin like a london broil--is that the same thing?)
Thanks!