While shopping used is indeed an option, it is a veritable minefield of potential disaster for one with zero experience in evaluating everything from basic function of controls and mechanical assemblies, to playability, to actual current market value. In short it’s a very easy way to buy a klinker you will be unable to use at all or without some work, which unless you know how to do that work, can add significantly to the initial purchase price.
That said, done right buying used is hands down the best way to get maximum bang for your buck.
In your situation, if you have a trusted mate with the requisite experience, enlist their help in your search.
Absent that, pass on any bass the seller is reluctant to have evaluated by a disinterested third party which would be an experienced luthier or instrument tech. While this will most likely entail a fee, it is usually comparatively small and potentially saves you buying a bass so wonky you lose interest before you ever experience your first ah ha moment in your quest for bass nirvana.
If you have no trusted mate or desire to arrange someone to survey used basses for you, my advice would be to stick to a physically close reputable retailer with an established rep for quality customer service. You will pay more for a bass than you would for the same bass in the wild or by mail, but you will also be buying the collective knowledge and reputation of the people and business you trade with. In that situation you could buy a used bass with some confidence. Shops like that can also take care of basic maintenance like installing fresh strings and a good set up, often included in the purchase price or for a reduced price at the time of purchase. If such a shop is close enough it can also supply the single most important next step in your evolution as a bass player. Lessons
Trust this self taught individual, it is soooo much simpler and easier to learn it right the first time than it is to labor alone as you build in impediments to your ability to fully exploit your instrument that you will later need to unlearn before you can get it right. The absolute shortest route from green bass owner to competent bass player is lessons from a professional musician. While lessons from a pro bass player would be ideal, any competent musician can set you on the right path so much faster than you can by casting about in the dark for how to get your bass, hands, and ears to pull together.
If lessons are not an option there are plenty of decent self teaching method books that are better than simply going in blind.
Best of luck and don’t give up. In the words of my favorite culinary personality, your patience will be rewarded.
