Well you could try the cheap Roxsen Nikon lens to M42 camera adapter, which, despite being inexpensive, even comes with a padded carry case.
Then you just need an M42-SA adapter and your in business. You dont get infinity focus with this adapter combo, just close ups and macros, and for this reason I use my Roxsen adapter exclusively for my two Nikon Micro Nikkors, where this adapter combo gives you a magnification advantage. For Nikon lenses that I want to use at infinity, like my 35mm f1.4 AIS and 105mm f2.5 AIS, I convert them to SA mount.
The other option is a Roxsen Nikon lens to PK adapter, which unlike the former Roxsen adapter, is an optical adapter, ie: It contains an optical element in the adapter to correct the difference in registration distance so you can get infinity focus. I dont like optical adapters as they can reduce image quality and introduce CA problems, but its not that expensive either, so its worth a look.