LED strip lighting joining cuts?
Edit 

For some LED strips once you cut the strip that's it.

That particular brand is linkable once it has been cut. It appears to be DC as opposed to AC so the link would require the correct polarity. 

Looking at the product page it does not appear to show any link connectors, rather just the live ends (the part that feeds from the transformer).  But that is not to say it may or may not come with a couple of linkable connectors.

Some hardware stores stock basic LED strips like this but chances are they won't sell individual parts. And there is  a high probability it may be slightly off in size if you did find one that was a similar match. With the sensitivity of LEDs that could lead to the LED working part of the time or not working at all after it has been installed.