I've been there often and we were just there in December.
Here are some tips:
1. There's a Disney Character Warehouse in the outlet mall on Las Vegas Blvd South that somebody has already mentioned. It's actually in one of the annex buildings...at the south end. It's very good. It has a lot of the 50th anniversary items from
Disneyland right now. I went there twice and bought a lot of stuff twice.

Can't beat the price of DL baseball cap for $1.29 or a DL tee for $3. Got a nice Incredibles baseball shirt for $12.
2. If you don't have a car, there is a Strip Trolley that you can use. You can buy a day pass and it goes up and down the strip. You can hop onto other trolleys at the end of the line and go to the two major outlet malls (the one I mentioned above and there's one near downtown.) I've never used it (we had a car this last trip) but it looks ok. Much cheaper than the monorail.
3. Cheap eats? Ellis Island on Koval Road. If you go to the restaurant, ask for the steak special (it's not on the menu). Salad/soup plus steak, veggies and potato for $4.95. It's a good quality steak and the food is good. If you go to the microbrewery, they've got amazing bbq chicken and ribs. Half chicken and slab of ribs with corn, beans, coleslaw for $7. You won't be able to finish it....you should split it...it's huge.
4. Good buffet? Paris for "brunch". Don't know if you're going to be there over a weekend but this is what we did. We lined up for Champagne Brunch on a Sunday morning (they have it on Saturdays too) at 10:00 am (it starts at 11 am). By the time we got to the cashier, it was 10:30. She couldn't sell us the champagne brunch because it was too early but she could sell us the breakfast which was $7 cheaper. She said, the food changes over at 11 so we'd get the same food as the brunch, just not the champagne. We said, ok...and the food did change over. We had yummy breakfast for the first trip to the food stations (including crepes) and then at 11, we had seafood and souvlaki, and...well, you get the picture. LOL It was very tasty too. It's crowded at this time so plan ahead.
This buffet technique works at other buffets too but we loved Paris.
5. Star Trek Experience at the Las Vegas Hilton. If you're even mildly interested in Star Trek, you have to go here for the two "rides". They're quite fun...especially the Borg one. Then go shopping in the Star Trek shops there and have a drink at Quarks. I've heard you can get half price tickets or some sort of discount ticket at the discount ticket place in the Coke bottle building near MGM.
6. Flamingo Habitat. At the back of the Flamingo, they have flamingos, ducks (really beautiful ones), pheasants, cranes and koi in a very nice garden setting. They used to have penguins but they got shipped off to a zoo in Dallas. It was nice (and free!) Very peaceful.
7. Drink lots and lots of water. It's a desert and you can tell. Your skin will dry out faster than you've ever experienced.
8. AVOID the Circus Circus buffet and the Imperial Palace buffet. Really.......really, really avoid.
