Located at the corner of Jl Monkey Forest and Jl Raya Ubud, this is a double storey warren of stalls bursting at the seams with wood carvings, batik shirts, sarongs, and all manner of other souvenirs aimed specifically at tourists. The merchants here haggle with tourists for a living, and think nothing of asking for ten times the going price, so try to establish a baseline before you go in to buy. Most of the merchants downstairs will lose interest if you try to get a reasonable price. It is better to try the shops upstairs where you will find the same products often for sell at lower prices. You will still need to use your best bargaining skills of course. Try to avoid the period from 11AM-2PM when tour buses from further afield tend to arrive en-masse.
If hiring a car for a day, it might be worth it to make a stop in Tegallalang, where they are geared more towards wholesale buyers. The Sukawati Market is crowded and sells trinkets in bulk as well, but quality is dubious.