şay

/ ʃaj /

Cases

SingularPluralWhen to use it
nominative şay the five-kopeck piece şayla the five-kopeck pieces the plain dictionary form — the doer of the sentence
genitive şaynı the five-kopeck piece's şaylanı the five-kopeck pieces' the owner — whose it is
accusative şaynı the five-kopeck piece (as the object) şaylanı the five-kopeck pieces (as the object) a specific, known object — whom or what
dative şayğa to the five-kopeck piece şaylağa to the five-kopeck pieces direction or recipient — to where, to whom
locative şayda at / in the five-kopeck piece şaylada at / in the five-kopeck pieces where it is; also having — mende bar, "I have it"
ablative şaydan from the five-kopeck piece şayladan from the five-kopeck pieces where it comes from; also "than" when comparing

The endings are the same ones the pronouns wear — that page explains when each case is used.

With an owner

One ownedSeveral owned
my şayım my five-kopeck piece şaylarım my five-kopeck pieces
your şayıŋ your five-kopeck piece şaylarıŋ your five-kopeck pieces
his / her şayı his / her five-kopeck piece şayları his / her five-kopeck pieces
our şayıbız our five-kopeck piece şaylarıbız our five-kopeck pieces
you all's şayığız you all's five-kopeck piece şaylarığız you all's five-kopeck pieces
their şayları their five-kopeck piece şayları their five-kopeck pieces

The overlap in the last rows is real, not a mistake: şayları can mean "his / her five-kopeck pieces", "their five-kopeck piece", or "their five-kopeck pieces" — context decides.