I use mostly Mouser but DK as well. I get free deliveries from Mouser for orders over x €, can't remember the exact amount. But it is very similar to Digikey, and should work the same for you too. My reasons to favor Mouser are that they have a distribution center in Stockholm Sweden and stuff moves quickly over the border to me. Also both are in EU so no hassle with customs.
For small orders i use a group order service from Digikey. This is something you cannot do since it is run by a Finnish small company as a free service. Very handy when you only need a couple of components, or something not stocked by Mouser. You only pay for the letter from this company + a tiny premium for handling.
When you are after budget components, i too recommend Tayda and Futurlec. Some time ago i made a series of 40 kits for a CNC mill spindle speedometer using 1" 7-segment displays. Tayda offered hands down the cheapest components and got the order for 200 of those + plenty of other stuff.
Another time i ordered a few hunderd small terminal strips from Tayda but they somehow lost the shipping. The order showed as collected but they coudn't locate it so they promptly refunded me. The only damage was lost time which in this case was not critical. Other than that, clockwork.