about 4000 Taka a month if you take permanent membership then whatever you spend each month on beer/coffee/food/tennis court rental. ( currently a beer is 200 BDT )
if you take temporary membership you buy tickets in books of 1 or 2 ooo BDT, which gives you 800 or 1600 BDT ( thus membership cost is in the ticket )
Give them a ring today as they might be closed over Eid