I have not tried many brands of watercolour paint but have found that cheap is not worth using.
the cheap paints seem to "cauliflower" more and granulate more and dont seem to have the colour density that better paints have.
I started with Winsor and Newton travel watercolour pans but now have moved to Sennelier. They have an amazing colour density and because they are mixed with honey have a lovely fluidity that really helps when I'm laying down colour.
Pans or Tubes?
I started off with pans in my Sennelier travel set and then bought tubes to top them up with.
You can get this here:https://www.jacksonsart.com/sennelier-watercolour-travel-box-set-of-14-half-pans-brush