Any idea what kit this is?

It's a bit hard to tell from this picture, it might be a C series Sterling scale Fokker. I believe this was denoted C-6. Many of the C series kits had their fuse built like a conventional stick and tissue model. This one appears sheeted. This could also be due to the box shape of the Fokker. I know Berkley made some scale like kits which used interlocking planking which were glued on and then the radius was sanded into them. Old models can be quite problematic. The tanks are buried in some of these models and gaining access means a bit of surgery. The glue especially if Ambroid was used has shrunk out of the joints leaving very little  strength. Sterling used a poplar plywood which by this day and age is so brittle it probably will pull the screw of the bellcrank through it. Oil soaking and creepage is another problem in the engine crutch area.

Sterling's plans were very lacking. Plans were never full size with the exception of the C-series kits. The plans for these kits were drawn very accurately and to scale. You could virtually replicate any part from them. They were also 2-3 pages opposed to one sheet from their conventional kit plans. While the plans were drawn with quality, the wood as usual was incredibly heavy and hard. Reason being is that these kits had some very intricate die cutting due to the stringers and longerons used to make the fuse. Soft wood would more or less pulverize during the cutting process and quite honestly the hard stuff wasn't much better.

If this is indeed a Sterling kit, a new in the box kit generally brings anywhere from $70-$100. These still bring pretty good money depending on the model as some were quite favorable over others. Box art and condition is everything when it comes to kit collecting. However, due to their scale appearance, these kits were quite appealing to the scale builders as weight isn't as much of a concern as it is to stunt flyers. The upper wing connection of these planes were poorly designed. It wasn't uncommon to shed the wing if it was built per the plan. While this wasn't something that happened immediately, it could happen. The wings were built, covered, and the strut was just inserted through the small opening which generally was a sloppy fit. Later some of the plans added that you glue small scraps of balsa on the inside around the strut and double glue these penetration then cover the top of the wing on the model.

Dankar, a member of this forum is quite knowledgeable in these kits. He was selling some of these kits a while back. Many times these kits had spun aluminum parts for one reason or another were missing from kits due to people losing them or using them on another build or just replacing crash damage. Dankar would also be more knowledgeable to costs of these kits. I have plans for the C series PT-17. Ken