Which Friends characters were really the best friends?
Haskell, 187 bytes

f=g.(&gt;&gt;=(q.words)).lines
g t=p"CJMPRS"&gt;&gt;=(\k-&gt;show(sum.map snd$filter((==k).fst)t)++' ':k++"\n")
q[n]=[("",read n)]
q[n,s]=[(k,read n)|k&lt;-tail$p s]
p s=map concat$sequence[[[],[c]]|c&lt;-s]


f is a function that takes the input, as a single multi-line string, and returns the multi-line output as single string. Probably plenty left to golf here.

λ: putStr test1
504 CRS
1 J
199 J
345 MP
980
2000 CJMPRS

λ: putStr $ f test1
980 
2504 S
2504 R
2504 RS
2345 P
2000 PS
2000 PR
2000 PRS
2345 M
2000 MS
2000 MR
2000 MRS
2345 MP
2000 MPS
2000 MPR
2000 MPRS
2200 J
2000 JS
2000 JR
2000 JRS
2000 JP
2000 JPS
2000 JPR
2000 JPRS
2000 JM
2000 JMS
2000 JMR
2000 JMRS
2000 JMP
2000 JMPS
2000 JMPR
2000 JMPRS
2504 C
2504 CS
2504 CR
2504 CRS
2000 CP
2000 CPS
2000 CPR
2000 CPRS
2000 CM
2000 CMS
2000 CMR
2000 CMRS
2000 CMP
2000 CMPS
2000 CMPR
2000 CMPRS
2000 CJ
2000 CJS
2000 CJR
2000 CJRS
2000 CJP
2000 CJPS
2000 CJPR
2000 CJPRS
2000 CJM
2000 CJMS
2000 CJMR
2000 CJMRS
2000 CJMP
2000 CJMPS
2000 CJMPR
2000 CJMPRS