"Shooting Stars, Comet 220s, Cleansweep Fives"
-- advertisement in the Daily Prophet (DP4)
Splinter and Kreek’s is a company selling used brooms (DP4).
Their advertisement describes Splinter and Kreek's as a place at which to "buy your second-hand brooms", listing some out-of-date models. So this is presumably a second-hand broom shop, though it's possible they sell new brooms as well. The ad doesn't seem too effective, though, as the store's location is never given; it is likely in Diagon Alley, but we don't know for sure (DP4).
"Splinters" are tiny pieces of wood - the last thing you want to be sitting on top of on a transportation broom! "Kreek" may imply the sound a secondhand or older item will make once it is no longer new. Neither name engenders a feeling of security about their quality. Would you buy a secondhand broomstick from them?
Although the date printed on the Daily Prophet Newsletter DP4 is 1 October 1999, the timeframe for events is 1992-1993.