Who builds it
Web app work is not the same as website work, and I will not pretend it is
Most BD clients searching for a web application development expert have been burned at least once. The story is almost always the same: a cheap team quoted 40,000 BDT, delivered something that demoed beautifully on the project manager's laptop, and then fell apart the moment three users logged in at the same time or the boss tried to export a report. By the time you are reading this page, you already know a real application is not a WordPress theme with a contact form bolted on.
I am RH Fardin and I have spent the last five years building exactly this kind of software for Bangladeshi businesses, agencies and a handful of overseas founders who hired me directly. I do the discovery call, I write the data model, I design every screen, I write the backend, I push the code, I configure the server, I sit on the launch call. There is no agency middle layer, no fresh junior practising on your project, no account manager translating your bug report into something the actual coder will misread.
What that means for you is uncomfortable for most agencies but honest: you get one phone number, one inbox, one person who can answer 'why did the invoice total round wrong last Tuesday' without scheduling a meeting. It also means I am picky. I take on a small number of application projects each quarter because every one of them needs real architecture thinking, not a template swap.
If your idea is a thin form-plus-database, I will tell you that and quote it in the 50,000 to 90,000 BDT range. If it is a multi-tenant SaaS or an internal operations tool with role-based access, attendance, reporting and SMS hooks, that is custom territory and starts from 3,00,000 BDT.
The other thing you get is plain talk about cost. When a vendor quotes a web app in BDT, every shortcut shows up somewhere later, usually as your data. I would rather quote you honestly today, take 50% advance and 50% on launch, and ship something that still works two years from now than win the deal on price and disappear when the bug list starts.
See pricing in BDT