Transaction in Entity Framework refactoring and best performance

Question

I try to use transactions in Entity Framework. I have 3 tables Personel, Prim, Finans. In Prim table you look SatisTutari (int) if i add data in SatisTutari.Text instead of int value adding float value. Transaction must be run! Everything is ok but how can I refactoring or give best performance or best writing Transaction coding!

I have 3 table so i have 3 entities:

CREATE TABLE Personel 
(PersonelID integer PRIMARY KEY identity not null, 
Ad varchar(30), 
Soyad varchar(30),
Meslek varchar(100),
DogumTarihi datetime,
DogumYeri nvarchar(100),
PirimToplamı float);

Go

create TABLE Prim
(PrimID integer PRIMARY KEY identity not null,
PersonelID integer Foreign KEY references Personel(PersonelID),
SatisTutari int,
Prim float,
SatisTarihi Datetime);

Go

CREATE TABLE Finans 
(ID integer PRIMARY KEY identity not null, 
Tutar float);

Personel, Prim,Finans my tables. If you look Prim table you can see Prim value float value if I write a textbox not float value my transaction must run.

    protected void btnSave_Click(object sender, EventArgs e)
    {
        using (TestEntities testCtx = new TestEntities())
        {
            using (TransactionScope scope = new TransactionScope())
            {
                Personel personel = new Personel();
                Prim prim = new Prim();
                Finans finans = new Finans();
                //-----------------------------------------------------------------------Step 1
                personel.Ad = txtName.Text;
                personel.Soyad = txtSurName.Text;
                personel.Meslek = txtMeslek.Text;
                personel.DogumTarihi = DateTime.Parse(txtSatisTarihi.Text);
                personel.DogumYeri = txtDogumYeri.Text;
                personel.PirimToplamı = float.Parse(txtPrimToplami.Text);
                testCtx.AddToPersonel(personel);
                testCtx.SaveChanges();
                //----------------------------------------------------------------------- step 2

                prim.PersonelID = personel.PersonelID;
                prim.SatisTutari = int.Parse(txtSatisTutari.Text);
                prim.SatisTarihi = DateTime.Parse(txtSatisTarihi.Text);
                prim.Prim1 = double.Parse(txtPrim.Text); 
                finans.Tutar = prim.SatisTutari * prim.Prim1;
                testCtx.AddToPrim(prim);
                testCtx.SaveChanges();
               //----------------------------------------------------------------------- step 3

                lblTutar.Text = finans.Tutar.Value.ToString();
                testCtx.AddToFinans(finans);
                testCtx.SaveChanges();

                scope.Complete();
            }
        }

How can I rearrange codes. I need best practice refactoring and best solution for reading easily and performance!!!