Value of my storm tower? and help price items

Hello. just want to know if this is worth anything. PLUS i would like to know how to price any item I find. finding cool items is the one thing making me want to play but i have no idea how to tell if an item is worth keeping to trade or use for a different build.

Sell Value: 925
Storm Tower
Old Book
Defense: 4
Chance to Block: 23%
Durability: 20 of 20
(Warlock Only)
Required Strength: 12
Required Level: 4
+10% Faster Hit Recovery
Adds 3-5 Magic Damage
I to Demonic Mastery (Warlock Only)
To Summon Goatman (Warlock Only)
Cold Resist 6%
Lightning Resist +12%
Fire Resist 6%
Poison Resist +6%
Attacker Takes Damage of I
Repairs I Durability In 33 Seconds

No value. It has no good affixes, no sockets, no good skill mods.

As for how to get ideas on value, see posts in this forum, we try to give some tips on what to search