Prioritize mana/wis gear. If you mostly group you probably won't be the primary luller, and if you are getting beat up your group isn't doing their job.
You are correct that Max Mana isn't always useful if you never run out of mana and are never at FM. However, your group may run into an emergency, and then you will be dumping mana. More max mana means you will probably have more mana available when said emergency comes.
Also, you will be prioritizing mana anyway if you ever decide to raid. More mana means more CHs in the chain before you oom.
If you are lulling a lot,
https://wiki.project1999.com/Donal%2...er_of_Mourning is a good piece, albeit pricey for your current budget. Then you won't waste any mana on lulling.
https://wiki.project1999.com/Water_S...f_the_Forgiven is cheap, and is very useful when combined with lull.
https://wiki.project1999.com/Donal%2...es_of_Mourning are a free heal, but the cast time is lengthy. Probably not too useful in a group, but it could save mana if you are healing someone who is taking a quick AFK break.
You could also just save up for Epic, since that is going to be your most important piece. I know having crappy gear can be annoying psychologically, but that would be the best bang for your buck.