Pete,

I run a Systemdek turntable that I've had since the 80s (and it's still going well!) with a REGA RB250 arm and use a GRADO Black.  This sounds very good to my ears and the GRADO only costs around £40.  It is also possible to upgrade when the time comes for stylus replacement.  Much depends on what one considers a "sensible price", fortunately these days there seems to be a good choice of cartridge on the market.

I use a Goldring G1042 with my Rega Planar 3 and RB300 and have been very pleased with its sound.  Remember that it's not only sound that improves when you buy a better cartridge, but better tracking also reduces wear on your precious vinyl and particularly makes a difference when you get near the end of a record.  Personally, I think the Rega is good enough to justify the cost of the cartridge, but you pays yer money and takes your choice!

The Goldring range has the same cartridge body, but you pay incrementally with the sophistication of the stylus tip.  Prices start at £70 ish.

I bought mine from Mantra audio who gave a good trade in on my old Rega Elys, so they may do the same for you depending on what you have available.

As an additional bit of info, I recently bought a Cambridge Audio 640P which is an excellent upgrade from most built in phonostages  for the money(£60) and this works well with the Goldring and sounds great through my Naim Nait 5i/Dynaudio 42/REL Stampede setup.

 I have fitted the Grado Black and also using a Graham Slee phono stage (my Arcam A65+ has a phono stage, but it is rubbish) I have also upgraded the arm with a Origin Live structural upgrade; this has made a huge difference and I would certainly recommend it. I think I may consider a better cartridge at a later stage as the Grado seems great with this set up although I do take on board what Adrian says as many of my older albums are in a pretty dire state for this very reason.

At present my system sounds at least as good as my mates Linn (and rather cheaper!) off course some of this may be down to choice of speakers. room dynamics etc. but it is a vast improvement on the Pro-Ject (worthy machine tho' it is.) I am particularly impressed at the improvements in sound from the structural upgrade. This was £70 but has been worth every penny. I was a little suspicious of this originally but now am a total convert. My copy of Joy Divisons "Closure"has never sounded as good and some of my classical stuff really comes alive. Seems like Rega should really build the arm like this in the first place!