If your broke, don't even detail the car. You might go off the deep end and splurge on detailing supplies. I know first hand, it happened to me, oh its only $20 to take care of your car (bottle of AA, can of AA wax, AA wash, wash mitt, and some crappy towels), evolved into a $700+ hobby.
If you low on cash, I would either get a bottle of NuFinish (2X) a year or if you like to wax try Mother's or Meguiars cleaner wax once a month. Wash with Meguiars GC for $10 a gallon. Get a small garbage can to serve as the bucket, and get some old soft towels from the bathroom. Then get a bottle of PDMS rubber, vinyl, and plastic protectant. Get a bottle of automotive glass clenaer (20/20) Total price, like $30 or so.