Depends on what you are ordering. ICs, transistors, caps and resistors from Mouser are excellent. Some odd items, such as PL259/SO235 "UHF" radio connectors are better obtained elsewhere. Likewise, cases/cabinets/boxes, can sometimes be very costly from Mouser.
For us in the UK, orders are shipped free provided you order a minimum of 33 GBP (pre-tax) parts. That was the case on my last order some months ago.
The last time I ordered from Mouser I ordered LEDs, resistors, etc. in 1 off. That makes ordering for a particular project very straightforward.
Beware of eBay, Amazon and AliExpress, unless you are certain the supplier is not selling fakes. There are genuine suppliers on these market places, but quite a few sell garbage and fake ICs/transistors.
SJ