Bicycle Mechanics - Can I replace this crank?

Last year I broke one of the arms of a 1 piece crank on a cheap Huffy bike. I recently replaced the bike with a Trek 800, but I'd like to make the old one serviceable so i have a backup. My questions are:

1) when looking at different cranks, how do I figure out the required specs? i.e. what should I be looking for to know it will fit my bike? Or do cheap Huffy's even use standard parts?

2) I'm pretty good with following directions and figuring things out when it comes to mechanical types of things. Could I install a new crank myself or would I be better off having a local bike shop handle it?

3) Around how much would a cheap replacement be and around how much can I expect to pay if I take it to a shop to get done?

I'm trying to decide if its worth the money to get this fixed, worth the money to sell it as-is, or if I should just put it out with the trash. I am just looking for something adequate for city riding. Thanks in advance for any help.

Most one piece cranks are the same, other than a shorter size for kids bikes and a few older ones with different threads.

They are easy to replace... With a large adjustable wrench you should be able to do it.

I just searched Harris Cyclery, and they have one piece cranks for as low as $18... I am not sure of total cost, but I would be surprised to pay more than $50 for everything.

However, unless the bike is worth more than that, or has sentimental value, I would say you would be served best to either find a used crank somewhere (eBay etc) or buy a replacement bike for your backup from the thrift store (maybe $20 or $25 for a whole bike depending on your area).

If you sell it, you should probably sell it cheap as a parts bike, since if it is not worth you fixing, it is probably not worth someone else fixing.

If it were mine, I would find a cheap used crank, donate it to an organization that repars bikes and could use the parts (not a thrift store) or dump it.