Cartridge for my Linn Sondek LP12?

There are other variety of Cartridges that will work. But you have to consider- budget and matching to achieve the sound that suites to your taste. Having said that, I just completed setting up my LP12 with a Grado Prestige gold. I use it with an AES Ph-1 tube phono amp and a Line 2 SE. This combo seem to work well for me. Of course there are others that will better this combo but like you I do not want to spend over my budget. The Grado gold is spec at 5mv output which I beleive will track at 1.5gm force. I feel that I re-discovered my vinyls after I got my TT setup.
It replaced my old DUAL 604/ Pickering XSV3000 combo.
Just my 2 cents..... hope this helps.
"Vinyl Rules"

Thank you...my budget for this cartridge is not in the
Koetsu category.

If the Gold is a good match, I may pick one up.

BTW, I do not have a stepup transformer at present, so
sufficient output is a must.

I don't know how much under $300 your budget is, but if it's close then also consider the Grado Platinum, which is a very significant leap up from the plastic-bodied Grados, while being essentially of the same design, so no physical penalties. A lively and very refined cartridge, glorious with all types of music IMO, when properly set up. The better Ortofons are also very good (better than the plastic-bodied Grados), very detailed and sparkling quality, the OM20 Super and up usually being blown out the door for well under $300 on Audiogon.

I used to run a Linn K9 on my Rega p3 and enjoyed it very much. I now use a GOldring 1042 and it is slightly better than the K9 in all aspects. Linn's Asak is a slightly modified 1022.

The 1042 is a terrible rip-off in the US, but if you buy direct from the UK (from Mantra Audio) then it is quite competitively priced, at around $250 including shipping. They will also take your old K9 as a trade in for a discount.

I can't say it's the best out there, but it is well reviewed, and sounds quite good to my ears.