Frequency Standard - GPS or Rubidium?

Hi all,

I'm looking for some sort of frequency standard (10 MHz ref.?).

Ebay has rubdium standards for under $100.00 and there are GPS
controlled OXCO standards for $100.00 plus.

My question :
Is a 10-20 year old rubidium standard more accurate (even with aging
drift) that a newer GPS OXCO?

I can't afford a GPS corrected rubidium ( ~$700.00+).

I just want to recalibrate my so-so frequency counters .. to hopefully
within 10 Hz..?

Opinions?

Thanks for reading!

Cheers!
Bart