I would choose a chef's knife and a pairing knife. These two knives can perform all cutting tasks in the kitchen. I would buy the best knives I could afford. I would look for knives with stainless steel blades and three tangs in the handles.
During the time of purchasing kitchen items,buy good quality knives,always purchase a knife with blade 8-10 inches long which is suitable for many kitchen's tasks and other smaller than that.
The two most basic knives every cook needs are the paring knife and the chef's knife. Those would be the two to purchase if you cannot afford a whole set.