First of all, the first item you should buy with ur frost tokens MUST be either T10 chest, shoulder or head. You can farm,buy or nj your t10 glove/pants from Voa.
But which one first?
Buy shoulder first if u have already got another t10 piece (glove or pants)from VOA. (reason: to get the 2 piece t10 bonus ASAP)
Buy chest first if you have 95+ frost tokens,have 0 t10 gear,have been using a bad robe and t9 head/shoulder/glove/pants. (reason: getting some upgrade without breaking ur old T9 bonus)
Buy Head first if you have 95+ frost tokens,have 0 t10 gear,have been using a bad head,have too much hit,and t9 shoulder/chest/glove/pants. (reason: New t10 head gives haste/crit which are very nice if your have too much hit with ur old helm. for example, t9 helm gives hit.)
So it would be either Shoulder ---> Head -----> Chest ------> VOA drops (You can spend 60 tokens at gloves if you don't trust ur luck at VOA)
Chest ---> Shoulder -----> Head -------> VOA drops
Head ---> Shoulder -----> Chest -------> VOA drops
Don't buy anything till you have ur 4 pieces t10. In fact, you should buy Primordial Saronite with ur tokens and craft youself the Leggings of Woven Death.