Actually when you're done it is more than $1k because this lens is not very useful without a flash. It pairs best with the MT-24EX and I recommend anyone interested in the MP-E 65 to budget for the pair.
Personally I find the lens very cheap given what it can do. There really isn't anything out there that is comparable.
- You can achieve sharper photos at 5x with a Nikon 10x 10.5 WD objective on top of a 100mm macro, but then you're stuck at 5x.
- You can achieve similar (or greater) magnifications using a bellows, but it is extremely difficult to use in the field
- Reversing a 50mm may also provide >1x magnification, but again you are stuck at one magnification
- Minolta makes a 1-3x macro, but this is 1-5x
Compared with someone paying $13k for "just a bird lens" the MP-E 65 is a bargain.