The wealthy were the primary owners of instruments back then, and some were owned communally (Churches, etc). In 17th c England, an upper middle class person may have had a chest of viols (a collection of stringed instruments) used for entertainment at parties and such, but things like harpsichords were always for the upper class. The common man had no time or money to spare for such things. Less expensive instruments like pennywhistles, or folk (keyless) flutes and recorders were more in the price range of the average person. A lute would have been more expensive but still affordable enough for a troubadour to buy one, and they were guarded with ones life--ones instrument was ones paycheck if you were a musician, and often the only valuable thing you owned. But there is a reason why harpsichords were never a folk instrument, and were used exclusively for art music. They were usually built to order, and were not at all cheap. I have no idea how much one would have cost back then, but pretty much the best guide we have for such things is the fact that they were not a folk instrument ever, that they were always elaborately decorated and built of the finest materials, and made to order, and that the nobility held them in high esteem in every country in europe (they were a status symbol). The only way a common person would have access to one was if he apprenticed himself to a builder, or showed promise as a performer and acquired a patron, or perhaps through church if one was lucky. And professional composers and musicians usually came from wealthier families, or at least from established musical families (the Bachs, the Mozarts) or showed exceptional promise as I said above and acquired a patron. All harpsichordists also played the organ, and that was probably where one got ones start, and where one would have achieved notice or at least a salary so one could afford ones own instrument. Keep in mind also, that music was considered a pastime for the upper class. Again, the only music commoners would have heard would have been at church, at public performances (rare), or in taverns. If it is the type of instrument with an apprentice/master type relationship, building ones own was usually the end of ones apprenticeship--this is more like harpers in the British Isles, or perhaps violinists in Italy. But in order to have the leisure to pursue music as a career option, one generally had to have some other means of support while learning. Again, this is why many composers and performers, particularly on the keys, were tied to churches at first--that would be the only way they would have access to such an instrument.

Tavern music and folk music at the time was usually very simple as far as instrumentation--perhaps a rebec (in the renaissance and very early baroque---a simple three stringed fiddle), a flute of some sort often homemade, and a drum, again homemade.

Once I'm not at work, I'll come back and add more and some sources, but this is just from my learning and research as a harpsichordist and organist and music historian.