Of course, I'll give constructive feedback!
I actually don't colour a lot, so for me I would prefer a good brand and use it for a long time. I've tried before using inexpensive brands but most if not all of them have lower quality pigments - but if you're on a tight budget, the brand choices would probably be limited. Though I haven't used prismacolour pencils, I heard they are very high quality (but super expensive!).
For carrying around, I think maped colouring pencils (you can find them on amazon) aren't very expensive. I have the pack of 24 assorted colours (the pencil has a different colour on each end of the pencil) and I looked it up on Amazon, and it was around $9 CAD. I think the quality is pretty nice and the colours are also quite luminous (in my opinion).
If you don't mind about the quality of the pencil and just the brightness/vividness of the colour, you can always use some program (like photoshop or Gimp) to adjust the contrast and lighting (or even use your phone).
Sorry for replying so late, I've had lots going on this week. Hope you have a great day!