I started out messing with strands from Adafruit and learning the basics of microcontrollers but when some friends and I started playing with bigger projects (or just wanted more lights to fool around with in various things) we just ordered them by the 5m spool for 1/4 or 1/5 the cost on Aliexpress.
The pros of ordering domestically are faster ship times and likely some sort of QA/return policy. But if you just want to order 10 or 20 or 50m of RGB LEDs to screw around with FastLED projects and can handle waiting 1-3 weeks for shipping (even if you pay extra for faster shipping it's typically still cheaper) you can get many more lights per dollar spent.
https://www.lowes.com/pd/GE-Color-Effects-50-Count-32-6-ft-M...