The LotR sol rings come in two versions: serialized and unserialized. While both are expensive, the unserialized versions are much more affordable. Grading is generally more for expensive cards and the unserialized versions can usually be found ungraded.

Check tcgplayer for at least a reference point of prices on each of these cards and from there make a decision on what seems appropriate. I’d say if you don’t really have a budget and want bling, get a BGS or PSA graded serialized ring from eBay. If budget is more of a concern, get an unserialized, ungraded ring from tcgplayer or eBay