The City of Oswego has a special weekend where the whole town has garage or rummage type sales. Call the city, but it is always in May. Mothers and more along with two other moms groups rent out the DuPage Fairgrounds around every Sept 9 and March 9. That huge sale starts in the morning on a Sat, but ends around 1 pm. Some buildings are open later with a half price sale starting at 11:30PM. It is infant, children, and maternity items. BAtavia also has a sale around the same time at one of their public schools. The catholic church in Sandwhich area usually has a clothing sale.
Their is a hidden gem in Aurora. On Lake St also called route 31, there is a thirft store in an anchore size building. On Thursdays it is buy 10 get 10 free. Prices are around 1 to 4 dollars for clothing, but most are around 2 dollars if that. It is next to Carson Piere Scot.
Have fun shopping!