For context, the statements about the burial come in the middle of a speech given by Stephen during his trial before the Sanhedrin. Thus it is not the Book of Acts per se stating these things, so much as recording what Stephen said. That said, interpreters have tried to make sense of Stephen's apparent mistake here for as long as there have been interpreters.
Part of the issue is that the obvious solution - that Stephen confused two purchases of burial land - has its own difficulties. Some interpreters1 have considered Stephen's fault to be in a single word - "Abraham" - and interpret Stephen as mostly alluding to Joseph and his brothers. While Jubilees says Joseph's brothers were buried with Jacob at Hebron, there are other traditions as well that they were all buried together at Shechem. Under this interpretation, Stephen simply mistook the original purchaser.
The difficulty with this reconstruction, though, (and others like it) is that nobody ever bothered to make a correction. Stephen is obviously one of Luke's heroes - indeed, probably no one in Acts is depicted more similarly to Jesus than is Stephen. So why didn't Luke fix up Stephen's supposed error? Similarly, none of the scribes who copied Acts made a correction here either; yet in many other places we find scribes "correcting" something in the manuscripts when they think it was wrong. So why not here?
This has led commentators to consider alternative options. Perhaps Stephen isn't quoting Scriptures at all but alluding to some local tradition. Perhaps Stephen uses some unknown variant of the LXX. Perhaps he considered Jacob's purchase as an agency for Abraham. Or perhaps because Shechem and Hebron are geographically not far from one another, they were considered one region in that day. Etc...
A number of modern commentaries,2 though, follow the approach of F.F. Bruce3 (at least he seems to be the originator as best I can tell) that Stephen creates an amalgamation of the two accounts in order to shorten it. Rather than take the time to explain that they carried the bones of Joseph to Shechem to be buried in the tomb purchased by Jacob and the bones of Jacob to Hebron to be buried in the tomb purchased by Abraham, instead he "telescopes" the narratives into a single one.
The basis for this idea is in other parts of the same speech. For instance, in Acts 7:2-3 Stephen combines the call of Abraham which happened in two separate accounts into a single account/calling. Or again in verses 6-7, Stephen combines God's statements to Abraham in Genesis 15:13-14 with God's statement to Moses in Exodus 3:12. In other words, there is already a pattern of this in Stephen's speech, so it shouldn't surprise us if he were to do the same thing here in verses 16-17. Why he does these things might be another question. But it might simply be that Stephen does this in order to shorten his already lengthy account.
1 cf. Calvin's Commentaries, Vol. 36: Acts
2 e.g. Bock (BECNT), Marshall (TNTC), Polhill (NAC), Witherington III (SRC)
3 The Book of Acts: New International Commentary on the New Testament (NICNT)