Semiconductors are not cheap on LCSC or JLCPCB. Maybe sometimes twice the price of Mouser or Digi-Key. But on passives, in any case these are cheap.

As for a MosFet, there are thousands available! I would not bother too much and select any one that is on stock and is in my budget.

For example:

250mA https://eu.mouser.com/ProductDetail/...x%2FNVUw%3D%3D

4A: https://eu.mouser.com/ProductDetail/...T0hBeH7w%3D%3D

Ioannis