1: Being 5'9" has little to do with what size bike to get. Go here to figure out how long a top tube you need.

2: The assembly of a one geared bike requires nothing that normal weekly maintenance doesn't require. You can look here and here to see what is required. You will see that $25 will get you the tools you need to assemble a Kilo TT. That, with the bike is within the budget you gave.

3: If you are too lazy to do #1 and #2 seems above your abilities, look here for transportation.