Straight answer: a Progressive Web App or a tightly-scoped single-purpose app - bookings, ordering, fee collection - fits my fixed tiers of 50,000 / 90,000 / 1,50,000 BDT. A proper custom app with a real backend, accounts, user roles and payment integration starts at 3,00,000 BDT, and the smallest engagement I take is 50,000 BDT. The number depends on what the app must do, how many user roles, which integrations (bKash, Nagad, SMS, maps) and whether it needs to be on the Play Store and App Store. I quote one fixed price after a scoping call, not a vague range to drag you into more meetings. Payment is 50% advance, 50% on launch via bKash, Nagad or bank. And if someone in Uttara quotes you 20,000 taka for 'a Play Store app', that's a broken WebView - walk away.