Dont overpay for a K1000!  If you're looking for a mechanical, manual 35mm camera of the sort photography students are assigned to purchase there are a number of superior options at better prices.  Apparently some years ago some photography instructors began telling their students to get K1000s.  This is probably because they were dirt cheap in comparison to other brands.  The K1000 was, after all, a budget entry-level model and was designed and built as such.  Over the years there has developed an inexplicable cult of the K1000 among photography students, which has driven the price of these cameras and Pentax lenses far above what is justifed by their quality.  I wish to offer my thoughts on several alternatives. 

The Minolta SRT series are top-notch match-needle manually metered and fully mechanical cameras and are plentiful and cheap.  They are well known for their "built like a tank" all-metal build quality.  If you google "minman minolta manual" you'll find an extremely informative website detailing all the variations in this series.  A Minolta is also an excellent choice for the student on a budget because Minolta Rokkor lenses are much cheaper on ebay than Pentax SMC lenses and are just as good.  Aftermarket lenses in the Minolta MD mount are absolutely dirt cheap. 

The Canon FTb is my personal favorite.  Like the SRT series, it is a an all-metal, mechanical, match-needle metered SLR.  Likewise, lenses in the Canon FD mount are better and cheaper than their Pentax rivals. 

The Minolta SRT series and the Canon FTb have the same basic features as the K1000 and are built better.  They are entirely mechanically operated except the light meter.  That is, they function and fire at all speeds without batteries.  They share only one major shortcoming which is easily remedied.  They were both designed to use 1.35 volt mercury batteries to power their light meters.  Mercury batteries are no longer available due to environmental regulations.  You can buy 1.5 volt alkaline batteries that will fit but this will throw the meter off by at least two stops rendering it useless.  There are two solutions.  First, you can buy Wein air cells from B&H or Adorama in New York.  They discharge the proper 1.35 volts but only last a few months after removed from the factory packaging.  Second, if you are going to have the camera overhauled anyway, the technician can recalibrate the meter for 1.5 volt batteries. 

Canon also made the AT-1, the manual version of the AE-1.  It shares the same basic capabilities as the FTb but it has an electronic shutter and will not fire without a battery, though it was desiged for use with an alkaline battery still readily available.  It also has many plastic components rendering it smaller, lighter, but less durable than the FTb. 

If you are determined to overpay for your 35mm SLR, buy a Nikon.  The F2 Photomic and FM were the best manually-metered SLRs ever built, and prices for these cameras on ebay will reflect that.  Classic Nikon collectors are a hard core bunch.  Oh, and be prepared to shell out a mint for old Nikkor lenses, too. 

If you must have a camera that accepts Pentax K-mount lenses like the K1000 try to find a Ricoh XR-1 or Sears KS-1000, which is the exact same camera made for Sears by Ricoh.  It is a mechanical, match-needle manually metered camera designed for 1.5 volt alkaline batteries.  It's only disadvantage vis-a-vis the K1000 is that it is built almost entirely of plastic.  Nonetheless, contemporary reviews in Popular Phography and Modern Photography gave good marks to its build quality.  Moreover, this camera displays both set shutter speed and f-stop in the viewfinder.  The K1000 does not. 

As to lenses, I offer the following thoughts.  You can find 50mm lenses for both Canon and Minolta with a 1.4 maximum aperature far more cheaply than a comparable Pentax SMC lens.  There are 50mm lenses in the Pentax K mount made by other manufacturers, like Ricoh, Vivitar, Cosina and others, but the quality of the optics is inferior to one from Pentax, or Canon or Minolta for that matter.  Canon 50mm f/1.8 lenses are dirt cheap.  Likewise Minolta 50mm f/1.7 or f/2 lenses. 

If you want an excellent wide angle lens with a fast aperature, get a Kiron.  Kiron made great 24mm f/2 and 28mm f/2 lenses in the 80s to fit all the major brands, and today they can be had for a fraction of what you'd pay for such a lens from an original manufacturer.  Of course you could always get an original manufacturer lens with an f/2.8 maximum aperature; they are plentiful and in 28mm at least not expensive. 

For a telephoto get a Celtic series lens for your Minolta.  They are dirt cheap today and optically superior to aftermarket products.  Hell, even a 135mm Rokkor isn't that expensive.  Canon's 100mm f/2.8 and 135mm f/2.8 are likewise plentiful and cheap. 

Don't buy zoom lenses for your old manual-focus SLR.  The optical quality of zoom lenses from twenty and thirty years ago is far inferior to what it is today.  Stick with the prime lenses which were as good then as they are now. 

The Canon FTb and AT-1 accept lenses in the Canon FD mount.  Run searches on ebay with the focal length and lens mount.  For example:  "28mm Canon FD." 

The Minolta SRT series accepts the Minolta MC or MD mount.  The MC is simply the earlier version of the MD; there is no practical difference for an SRT user.  The downside for the ebay shopper is that to run a thorough search you have to search twice for the same lens, for example "28mm Minolta MD" and "28mm Minolta MC" in order to make sure you don't miss something. 

So go tell your photography instructor you're not going to settle for a crappy little K1000!  Buy a better camera for less and have fun!