Master Pages: Really simple concept and easy to implement. Do the bare minimum of reading then just create one and use it with a couple of pages - you really can't go too far wrong with these. Maybe check something like this out:
http://www.devx.com/dotnet/article/18042
Repeaters: Little bit more involved - more to learn (data binding, basic info on the page life cycle) but still very easy to learn.
simple example can be found on w3c schools:
http://www.w3schools.com/ASPNET/aspnet%5Frepeater.asp
if you are binding to info from a DB, best to use a datareader rather than a dataset:
http://aspnet.4guysfromrolla.com/articles/050405-1.aspx
Good luck fella