http://www.ModelExpo-online.com/ema068Do a search on Airfix, Heller, and Revell. Some good deals to be made on some unusual subjects. Of particular interest are:
Airfix:

1/72 Westland Gazell for 81 cents. Good surface detail, fit is good, includes decals for 2 military versions, 2 pilot figures, molded in grey plastic with clear for the windows. With some scratchbuilding you can turn it into a civilian chopper, like a medical ambulance or news chopper. The blades can be built as set for flight or stowed. I bought 3 of these babies. One of them is going to get some spare WW2 Luftwaffe rockets I have lying around from a Bf109G kit I built, hehehehe.

1/72 scale astronauts for 68 cents, with 2 lunar rovers and some fictitious gear. Molded in soft plastic, like toy soldiers, they aren't the best figures out there, but they're the only astronaut figures I can find. They clean up ok and can be detailed well with a fine-point brush.

HMS Mauretania for $4.40 is a steal. Most shops sell it for around $16. You can get photoetched brass details for it if you're a hard-core modeler.

"2001 A Space Odyssey" the Orion space shuttle for $2.80, molded in white and includes decals for both the version seen on the box and the Pan-Am version used in the movie. Detail is ok, fit is ok, but it could use a scratchbuilt interior (it doesn't come with any at all) and a better forward view window. Mounts on a black display base (no landing gear).
Heller:



1/43 Mercedes C9, Jaguar XJR9, and Porsche 962 race cars (sold separately for $1.43 each). Molded in white with vinyl tires, no driver figures (boo!), fairly basic interiors, easy assembly. I bought a 1/48 flight crew set that I'm going to convert to race drivers and track crews.

Ariane V rocket for $2.70. One of the bright spots in the European space contingency and one of the better models out there.
I picked up the three Heller F1 race car kits (Williams, Lotus, Beneton) for 81 cents apiece and the best things about those kits is that they're cheap and include driver figures. Decals seem ok but the cars themselves could use some better suspension detailing. If you're a scratchbuilder you could probably cobble together the proper suspensions, but I'm not much of a F1 fan so what comes out of the box is almost good enough for me.