In this article, we will list the most common items that can be shopped from vendors. These are split into several categories and follow your character progression. Please, keep in mind that we will refer to your character level as clvl from now on.
There are some tricks for fast shopping (hover or click on a vendor for a sample image):
Socketed Items
In Acts 1-2 Normal, vendors sell non-magical items with up to 3 sockets, if the item allows for it. Vendors from Act 3 onwards will only sell magic items. These socketed items are perfect for your starting (or in some cases later) runewords, or just adding gems to help you through Normal. Here is a list of these items:
2-Socket Helm

Shop: Charsi
Clvl:-
RWords: Nadir
Notes:Alternatively, you can put 2 gems, e.g.
,
or 2 runes, e.g.

2-Socket Armor

Shop: Charsi
Clvl:-
RWords: Stealth
Notes:Useful for every hero in the game.
3-Socket Shield

Shop: Fara
Clvl:-
RWords: Ancient's Pledge
Notes:Useful for every hero in the game. Get the runes from saving the barbs in Act 5
2-Socket Staff

Shop: Akara, Drognan
Clvl:-
RWords: Leaf
Notes:Useful on any hero with fire spells for leveling up:
Sorceress (look for +3 Fire Sorc skills when shopping), Assassin, Druid and even Paladin with Holy Fire.
3-Socket Bow/Xbow

Shop: Charsi
Clvl:-
RWords: Edge
Notes:Essential for Summoner Necro due to Thorns Aura.
Used by all other characters when gambling, alongside Gheed's Fortune, to significantly reduce vendor prices.
2-Socket Wand

Shop: Drognan
Clvl:-
RWords: White
Notes:Can be used on any Necro Build - look for +3 Necro skills when shopping.
2-Socket Shield

Shop: Fara
Clvl:-
RWords: Rhyme
Notes:Rarely shopped. Can be useful on some builds.
3-Socket Armor

Shop: Fara
Clvl:-
RWords: Treachery
Notes:You can also make Peace or other 3-socketed runewords, but it is recommended to go with elite bases when you get to hell.
Magic Items
These magic items provide critical skill charges like Teleport, Lower Resist, and Life Tap. You can also shop for gloves, belts, and boots with some +Life or other stats if you haven't found anything better.
Staff of Teleportation

Level 1 Teleport (X/X Charges)
Shop: Ormus
Clvl:19
Notes:Shop at character level 19-23 - item
appears red (unusable) for easy visual scanning.
Lower Resist Wand

Level 1 Lower Resist (X/X Charges)
Shop: Drognan (NM)
Clvl:31
Notes:Shop at character level 31-35 for Level 1 charges - item
appears red (unusable) for easy visual scanning.
Life Tap Wand

Level 6 Life Tap (X/X Charges)
Shop: Drognan (Hell)
Clvl:91
Notes:Shop at character level 91+ for Level 6 charges (Uber preparation).
Gambling
Only your character level matters for gambling. Use Edge + Gheed's (30% discount combined) to maximize gold efficiency. It doesn't matter which vendor you gamble from. The price of items increases with your clvl.
When you gamble, there are the following odds for the item rarity:
- Unique 1:2000 (0.05%)
- Set 2:2000 (0.1%)
- Rare 200:2000 (10%)
- Magical 1797:2000 (89%)
Always gamble coronets, until they turn into circlets, for a better chance at getting Griffon's. If these roll well, they can be very expensive.

Here is the list of items:
Gull Dagger

Clvl:11
Notes:Limited dagger pool at this level increases unique odds.
Tri-Res Boots

+ Tri-Resistances
+ Faster Run Walk
+ Faster Hit Recovery
+ Magic Find
Clvl:43
Notes:Could potentially be very expensive, with the right set of stats and high resistances.
+3 Tree Skills Amulet

+ 3 Class Tree Skills
+ 10% Faster Cast Rate
Clvl:65
Notes:Some builds really benefit from these amulets, until they can make a great caster amulet.
These might be useful with MF or Life/Mana/Resistances.
Coronet

+ 2 Class Skills
+ 20% Faster Cast Rate
+ 30% Faster Run/Walk
+ X% All Res
+ 1/2 Open Sockets
Clvl:87
Notes:Can be expensive even if Magic with 3 sockets and +3 Class Tree Skills.
Dual Leech Ring

+ % Life Stolen Per Hit
+ % Mana Stolen Per Hit
+ Faster Cast Rate
+ Life/Mana/Strength
Clvl:91
Notes:Costs ~50,000 gold per ring with discounts.
+2 Class Skills Amulet

+ 2 Class Skills
+ Resistances
+ % Faster Cast Rate
+ Life/Mana/Strength
Clvl:95
Notes:Usually, making caster amulets is better
Late Game GG Magic Items
"Godly" (GG) magic items can exceed Uniques/Runewords for specific builds. These require precise character levels to hit affix level (alvl) thresholds for +3 Skill Tree modifiers.
3/20 Javazon Gloves

+ 3 Javelin & Spear Skills
+ 20% Increased Attack Speed
Shop: Charsi (Hell), Anya (NM/Hell)
Clvl:55
Notes:Costs 1 x
. Probability ~1 in 11,305 at clvl 75. Shop at clvl 68-74 or 75+. 3/20 Martial Arts Gloves

+ 3 Martial Arts
+ 20% Increased Attack Speed
Shop: Charsi (Hell), Anya (NM/Hell)
Clvl:55
Notes:Costs 1 x
. Shop at clvl 68-74 or 75+. Jeweller's Armor of the Whale

+ 100 to Life
Socketed (4)
Shop: Anya (Hell)
Clvl:70
Notes:Costs ~5 x 
Battle Orders Stick

Shop: Malah (NM/Hell), Anya (NM/Hell)
Clvl:75
Notes:Costs ~1 x 
+6 Javelin & Spear

+ 6 Javelin and Spear Skills
+ 40% Increased Attack Speed
Shop: Anya (Hell)
Clvl:75
Notes:Costs 20-30 x
.
Higher character level is better. +3 Traps Assassin Claws

+ 3 Traps
+ 3 Lightning Sentry
+ 40% Increased Attack Speed
Other + skills
Shop: Anya (Hell)
Clvl:75
Notes:Costs 10-20 x
.
Higher level increases Elite base probability.