How to buy electronic components for little projects?
The way I did it was to order other stuff I will need at some point to go over the minimum amount.

For the first project, that shouldn't be a problem at all. You will need


solder paste (ideally, both a syringe and a larger container)
flux
non-magnetic tweezers of various sizes


These alone bring you close to the threshold in many cases. Also, I've found that it's a good idea to standardize on one size of SMD two-pin passives, and get a book with 20 of each value (resistors at least, capacitors are useful if you build lots of filters), and if one value runs out (most likely 33Ω and 10kΩ) to get an entire reel.

Some other standard items that are always good to order are the components required for buck converters (i.e. a few controller ICs, inductors, diodes and capacitors) because almost every project will need a power supply.

After the third project, all I need to order now are project specific items that are generally specific enough to be costly on their own, and smaller projects like Arduino clones with a few peripherals I can do with just my regular stock.