Truck Forums - starting problem

Recently we bought a 2001 Sonoma, usally runs great but on the rare occasion it won't start at all. The first time it started but wouldn't run without me holding the gas down, then no problems for 2 weeks. The other day I left work and there was nothing, no dash lights no klicking when i turned the key, tried a boost nothing. Tried turnig the key 10-15 time and it started. ran great the rest of the day next day I noticed a click in my raido and the clock light going up and down, when I got to work and shut it off there was no starting it again. after work tried 10-15 times ran great. HELp please, they tell me at the garage they can't help if the problems not the when I go in.