Omg same dilemma ko dati, hirap talaga maghanap ng discreet and affordable! A few of us tried the manual pumps from Lazada, may mga silicone collapsible ones na super flat, pwedeng i-tuck talaga sa bra or pocket, and like P500-800 lang, sobrang sulit especially kung occasional lang use mo. Nakita ko din sa Shopee ang mga hand pump brands na may travel pouch, and one of my mum friends swears by those dahil walang hassle, walang batteries, at talaga sobrang quiet kaya pwede mo gamitin kahit nasa public ka. Kung gusto mo talaga minimal bulk, the silicone manual pumps are your best bet, lightweight, effective, at hindi ka mag-overspend habang nag-eexperiment ka pa lang with what works best for you.