You need something to put your tools in, and the tool vessel that is closest to perfect is available for free! A modest bucket is how almost everyone got started and how most of us still roll. The Bucket Boss is a great system. It’s versatile and you can even add hardware trays and bags sold as part of the system and depending on what you eventually figure your needs are.
As far as the actual bucket–You can buy one for $11 but were it me, I hit up my favorite painter or drywall contractor for one of his left overs.