Jurys at customs house or Maldron on Cardiff Lane might be best suited as these I believe to be nearest the 02.
I have not stayed in either and have no connection. Check reviews possibly on tripadvisor.
I thought you said you were never in Dublin - see below??
Since the O2 is on the Luas Red Line, anywhere along the tram line is equally well an option - and it might be cheaper. In general, if you want affordable accommodation in central Dublin, try any of the B&Bs along Gardiner St.
I have stayed in Clarion IFSC and would recommend it. Lovely rooms, great food and up the road from o2 - maybe 10 mins walk or less? No affiliation just a very happy customer and will stay there again for gigs.