The Nady SP-1 is an extremely inexpensive dynamic microphone designed for live shows and gigging.  While of course it can be used in the studio if you wanted to, I'd strongly recommend only using this for shows.  The mic has an on/off switch and isn't all that well built in general.  The only reason that I got the mic was because it came in a Musicians' Friend pack that also came with a cable and a stand, all at a very low price.  I used the mic for band practice, and shortly after getting it I stopped using it completely.  Getting this microphone was really just a bonus to getting a nice stand for me...

OVERALL OPINION

I purchased the Nady SP-1 in the mic/stand/cable combination pack a number of years ago - I actually got two of them.  I figured at the very least I'd have a few new stands and cables, and could use the microphone for band practice as an inexpensive mic to throw around.  For a little while, the mics definitely did the job for me, but this was a while back and before I even had a decent PA system to use, so it was really for the bare bones type of use.  I can't really say that the sound quality of the microphone is good, but within my set up at the time it got the job done for me in my situation.  I'd imagine that there are a lot of people out there who might be looking for an extremely cheaply priced and designed microphone for situations like I had.  However, if you're looking for any microphone halfway decent for practicing or for live shows, I would definitely look elsewhere as there are plenty of cheap microphones out there that sound way better than this and will last a lot longer as well.  I'd only recommend the Nady SP-1 if you're also in the market for a stand and a cable to go along with it, as that is the only way that this microphone would really be worth anything in my opinion...