Not really, but it depends on your definition of cheap and reasonable walking distance. It also depends what direction you are coming from, so you're not snarled up in city centre traffic getting to the car park
If coming from the southern end of the M50, you can park in Ballaly or Sandyford for 4.50 for the day and get the luas, which would avoid a lot of hassle.
AFAIK, All car parks in the city centre are a minimum of €3 an hour.
The Tivoli car park off Thomas St. is €2.50 an hour and has a daily max of 12.50.