You don't lose bitcoin, you lose FIAT !
Not true, if you buy 100$ worth of bitcoin on some shady exchange, ( which is ~ 0.02
BTC), and they have a standard fee of 0.001, which is ~5.5$ (5.5% in fees) currently, you lose both bitcoin AND fiat.
Either find another exchange where you can choose the fees yourself, or, buy more Bitcoin
Which exchange are you currently using ? Coinbase? I might know some better exchanges, depending where you are from.