Summary
Kaminsky was only able to get a one-year non-guaranteed contract last offseason, and after he was waived by Sacramento he was claimed by Phoenix, where he played in the previous season. Surprisingly, Kaminsky got consistent minutes during a stretch in the middle of the season, even starting 13 games. While his minutes predictably went down as the season progressed, he did a decent job during that time.

Kaminsky shot 37% from three this season, showing that he can still provide value as a stretch big. However, his finishing numbers at the rim have always been bad, which has made him an inefficient scorer overall. Combine that with his defensive shortcomings, and Kaminsky is someone that I wouldn't want to rely on in the playoffs, and the Suns have not during their playoff run.

I don't expect Kaminsky to get anything above the minimum, and may even settle for a non-guaranteed contract again, but I wouldn't be surprised if he makes it through the season with a team, since he's shown he can at least be an "innings eater" during the regular season.
 
Cap Considerations
Kaminsky will be an unrestricted free agent with a $1.7 million cap hold and Non-Bird Rights. This means that the highest starting salary the Suns could offer him using the Non-Bird Exception is $2.5 million. This should be enough to retain Kaminsky, since he settled for the minimum of $1.9 million last offseason. Alternatively, the Suns could use their Mid-Level Exception or Bi-Annual Exception to re-sign Kaminsky if he demands more than $2.5 million.

Other teams will have multiple ways to sign Kaminsky as even teams without cap space could possibly use any of the Non-Taxpayer MLE, Taxpayer MLE, or possibly even the Room MLE or Bi-Annual Exception to sign him. It's also likely that Kaminsky only gets minimum offers.