Yeah, the 50g respec is actually a CRITICAL gold sink to keep prices from inflating too high, since raiders eventually hit a point they they otherwise aren't spending much, since they're supplying their guild with materials and being allotted guild-supplied gear/consumables in exchange.
That being said...this IS classic. Your spec isn't actually that important enough that you need to change it frequently. Your gear and proper use of your skills is actually much more important.
http://www.wowprovider.com/?talent=1121 ... 05p55e104i . A solid universal Warrior spec for both tanking and PvP. The 4 points in defiance can be moved around to whatever you need for your specific needs (2/2 bloodrage, 1/1 last stand, 1/5 Defiance is also pretty common if your group is good about their threat management and you need an extra OS button). And obviously, you go ahead and decide which weapon type you plan to use for your specialization (though swords tend to be the most common tanking weapons, the difference is usually pretty minor until later, though you basically just want to make sure it's fast, whatever it is (for HS dumps). Flurry Axe is nice if you can get one).
Nothing else in prot tree matters because spamming Sunder armor was and still is the highest threat per action thing you can spend rage on. Shield slam is better then it was, but it's still hardly required for tanking.
And no. Paladin CANNOT tank, at all. It just doesn't happen (And any group they did tank could've been tank even better by a hunter's pet or even a Void Walker). They don't have the mana to consistently generate threat, Silence will result in a wipe, and all their damage mitigation is RNG based and isn't in the slightest bit reliable. Even as off-tanks they are behind Shaman, despite the difference in armor (the shaman get better avoidance stats). The only viable tanks in Classic are warriors, or for off-tanking Feral druids (since they at least have reliable mitigation, non-mana based, and a taunt).
For a paladin, it's holy or nothing (it does the best damage and brings massive amounts of support to whatever you're doing). What you do with your extra 20 points is up to you. Ret sub-spec for more damage burst, prot sub-spec for more support options with less burst, though still perfectly able to solo.