Define “Beckishe”. Are you talking about a silk coat with fancy embroidery (hundreds of dollars)? Do you mean plain (wool/poly or poly) “kapote”, which is a double-breasted frock coat (perhaps $100 if you shop around)? If you want something for Purim, consider checking the “steampunk” or “reinactor” oriented shops, who base their merchandise on what was popular the last time long coats were popular among the goyim (i.e. before King George V stopped wearing them on a regular basis, and they almost immediately went out of fashion except among Jews, similar to what John Kennedy did to hats).