My first fixie, help needed!

New stuff with shop labour is going to be pricey. Thats just it.

You do have lots of options including:

1. Find a second hand/pre-built track wheel. Don't have to get Mosquito to build you one esp not for an old beat up frame.
   
2. Make friends with folks with tools and get them to teach you. Do some reading on SheldonBrown.com about conversions and work out what you need.
   
3. Convert the bike yourself to just a singlespeed for very little money. That way you know you'll like the frame and only having a single gear and then its worth investing time/money into it.
   
   

Speak to Kiwibikes or similar (Brick Lane Bikes) about whether they can do it cheaper with 2nd hand stuff etc.