If buying raw coin get high AU.
If buying slabbed get MS.
You can really save a bunch of money and have beautiful coins by buying AU-55 to AU-58 gold coins like sovs, 20 francs, pre-1933 US gold etc. If you are in right place at right time and/or have good relations with dealer a lot of these can be had for near spot thus any current or future numismatic premium is free.
Get an understanding of how a local coin store functions (as a business). After establishing a sincere relationship with the people there, and making purchases, ask them to contact you if they get a batch of good looking sovs (or whatever but a range is best) come in to give you a call and you'll be down to buy a couple.
"Come in" typically means an unexpected, random walk in customer off the street. "Good looking" mean AU with eye appeal. "You'll be down to buy a couple" means you get to the store ASAP with the cash in hand, because you already have set the funds aside for this very moment, to buy right then and there the picks of the litter.
It goes without saying that if you run across a raw coin you know will grade MS but can buy at AU price.....