"Like Michelangelo" is a fairly specific term, since he was generally considered to be one of the finest artists in Florence and was treated accordingly. It's like asking how much money did musicians like Mick Jagger make during the 1960s/70s, it's not going to be a very useful sample size.

For the vast majority of artists during the Renaissance period, payment was handled through the guilds they belonged to. Their work would be displayed at markets where it could be noticed by rich patrons, who would then commission further work out of them. The guilds would ensure a fair price, and then the artist would usually receive monthly installments until his work was completed. Prices at this time were fairly good dependent on quality, a talented artist could commission a life-sized sculpture for about 130 florins, a fresco around 20.

To note on the modern equivalent of a florin, the value of money changed a lot during the reneissance, so it's difficult to create a useful singular conversion. However we do know that during Michelangelo's time a florin was generally worth several hundred modern US dollars, so a prolific artist could make a comfortable living, especially considering their room and board was paid for.

Now Michelangelo is special, since he was part of an elite class of artisans that didn't have to worry about guilds, since the strength of their reputation led to them being commissioned directly by patrons. Michelangelo is famous for his particular favor by the Medici family. During the reign of Lorenzo the Magnificent the Medici set up art workshops all around Florence and let talented locals try their hand. It was at one of these workshops were a 13 year old Michelangelo was discovered after sculpting a life-size statue out of marble. (Funny side story, the statue was of an old man, and when one of the Medici family saw it he joked that Michelangelo's statue was not realistic since the man still had all his teeth. Michelangelo immediately picked up his chisel and knocked several teeth out). Recognizing his talent immediately, the Medici family brought Michelangelo into their home, effectively raising him and in turn making him their in-house artist. As the prized artist of the richest family in the world, Michelangelo began to attract significant patronage and renown. Arguably his most famous work, The David, fetched him a staggering 400 florins, which was 40x the annual wage of a middle-class citizen.

So to answer your question, artists like Michelangelo, that is, famous and talented artists, could live an extremely comfortable life. They were feted by patrons and given presents of vast wealth to keep them happy. As long as their work continued to be beautiful and non-heretic, they were part of Italy's upper class. Michelangelo is unique, his work was beloved and he was paid accordingly. Although he constantly complained of being underpaid or ripped-off entirely, his work allowed him to live a relatively luxurious life, a status compounded by the favoritism the Medici family showed him throughout his life.

Sources:

The production of art during the Florentine Renaissance by Matthew Gream

The Economy of Renaissance Florence by Richard A. Goldthwaite

The Autobiography of Benvenuto Cellini is a very fun read if you're interested in this question. It's free online: http://www.gutenberg.org/ebooks/4028

In brief, Cellini's lifestyle varied a great deal as he gained or lost patrons. At one of the wealthiest points in his life, while he was patronized by the king Francis I of France, he had a salary enough to hire several servants, a fairly substantial home to live in (including a tennis court), and a wardrobe of fine clothing. He pays the junior silversmiths who work for him 100 crowns/year and between a salary and payment for pieces earns 4,000 crowns/year for himself. To put a sense of scale there, he buys half a farm for 200 crowns, is at one point promised the benefice of a largish abbey worth 2,000 crowns/year, and describes 4 crowns/month as inadequate (but not tremendously so) to maintain a family with six daughters.

However, Cellini's funding was frequently in flux. Getting underpaid or not paid at all was a frequent occurrence, and Cellini went through a large number of patrons. (Even in Cellini's own account, he comes across as a violent nutcase, so his turbulence may be more than typical.) Later in life, after leaving France, he accepts a salary of 200 crowns/year, although he hopes he'll earn more once his new patron sees his work.