It depends.

If you level from 1-70 with a lot of questing and instance runs where you loot, it's not so expensive to raise Enchanting on all the team. Just don't sell quest rewards or drops and you can fund a lot (but not all) of the mats you need. 200-300 skill is a pain and will cost you a lot of gold.

DEing quest rewards on all characters can be a great way to generate mats, either for yourself or for the AH. Enchanting using all the quest stuff helps mitigate the training cost dramatically. Same with old gear that gets replaced by newer dungeon drops.

However, if you powerleveled up (using RAF or friends) and/or didn't loot/quest much along the low level way, you will pay a hefty price to get your skill up on multiple characters. The ring enchants were good in TBC and will continue to be decent. I was very happy with my Shamans all having enchanting because of the ability to generate a fair amount of mats and the ring enchants.

You should definitely have enchanting on at least one of your team, if you do any kind of PvE dungeon runs. My new hunter team has the lead hunter with enchanting, and its been a piece of cake to skill him up and enchant the rest of the team's gear. Will I grab Enchanting on all the hunters? I don't know, it depends on if I stick with the team long-term.

Short story-- It's expensive, and I'd only recommend it on a team you know you're going to stay with. It gets even more expensive the faster you powerlevel through the low levels.