Idioms? (My uncle is A COUCH POTATO and he's always glued to TV.)

[Rebecca]

Hi there!
There're some idioms i can't understand like in these situations:
-My uncle is A COUCH POTATO and he's always glued to TV.
-Elena thinks her new WAP phone is the best thing SINCE SLICE BREAD.
-Pierre works on the checkout at the local supermarket. They PAY HIM PEANUTS.
Can anyone explain them to me, please?
Thanks in advance.

[Yankee]

Hi Rebecca

I have given you a dictionary link for each sentence:

-My uncle is A COUCH POTATO and he's always glued to the TV.
http://dictionary.reference.com/search?q=couch+potato&r=66

-Elena thinks her new WAP phone is the best thing SINCE SLICED BREAD.
http://idioms.thefreedictionary.com/best%2Fgreatest+thing+since+sliced+bread

-They PAY HIM PEANUTS.
http://dictionary.cambridge.org/define.asp?key=58318&dict=CALD
.

[Rebecca]

Thank you very much