Hi ck,
Welcome to the forum ck.
This has been asked and discussed thouroughly in july 2006 on the following forum link;
http://www.cdnpapermoney.com/cgi-bin/yabb/YaBB.pl?num=1153204109Basically, Repeater refers to the numerical pattern of the serial number regardless of the prefix, ABCxABC, where X can ber any number.
Whereas, a Radar has the numerical pattern of ABCxCBA, where X can be any number.
Apparently there are a few sub-classes of Repeaters as you will learn when you go to this link, however like common Radars, Common Repeaters occur 1 in 1000 notes. "A" class repeaters are 1 in 10,000. etc. Serial numbers that are both Radar and Repeaters I do not recall, and Repeater Inserts are another category in itself. Etc, you will get the idea.
Repeaters are not collected as widely as Radars yet, so they may likely not command much of a premium. It will also depend on the serial numbers too.
Have fun,
PD
Dei Gratia