Crates
Champion Crate 1 - 0.33 keys (3 crates for 1 key)
Champion Crate 2 - 0.20 keys (5 crates for 1 key)
Champion Crate 3 - 0.50 keys (2 crates for 1 key)
Cars
Dominus GT - 3 keys (Certified: 4 keys)
Takumi RX-T - 2 keys (Certified: 2.5 keys)
X-Devil MK2 - 1 key (Certified: 1.5 keys)
Road Hog XL - 0.75 keys (Certified: 1 keys)
Breakout Type-S - 4 keys (Certified: 5 keys)
Wheels
Crate wheels

Chakram - 1 key (Certified: 1.5 keys)
Photon - 2 keys (Certified: 2.5 keys)
Looper - 2 keys (Certified: 2.5 keys)
Lobo - 0.75 keys (Certified: 1 key)
Lightning - 2-3 keys (Certified: 3.5 keys)
Troika - 0.75 keys (Certified: 1 key)
Pulsus - 2 keys (Certified: 2.5 keys)
Discotheque - 2 keys (Certified: 2.5-3 keys)


Other wheels

Asterias - 0.50 keys
Zeta - 0.25 keys
Painted Wheels
Painted Sunburst

Black Sunbursts - 3-4 keys
White Sunbursts - 2-3 keys
Grey Sunbursts - 2-3 keys
Crimson Sunbursts - 3-4 keys
Pink Sunbursts - 3-4 keys
Cobalt Sunbursts - 3-4 keys
Sky Blue Sunbursts - 3-4 keys
Burnt Sienna Sunbursts - 2-3 keys
Lime Sunbursts - 2-3 keys
Forest Green Sunbursts - 3-4 keys
Orange Sunbursts - 2-3 keys
Purple Sunbursts - 3-4 keys


Painted Tunica

Black Tunica - 3-4 keys
White Tunica - 2-3 keys
Grey Tunica - 2-3 keys
Crimson Tunica - 3-5 keys
Pink Tunica - 3-5 keys
Cobalt Tunica - 3-4 keys
Sky Blue Tunica - 3-4 keys
Burnt Sienna Tunica - 2-3 keys
Lime Tunica - 2-3 keys
Forest Green Tunica - 3-4 keys
Orange Tunica - 2-3 keys
Purple Tunica - 2-4 keys


Painted Chakram

Black Chakram - 6-8 keys
White Chakram - 5-8 keys
Grey Chakram - 3-4 keys
Pink Chakram - 6-8 keys
Cobalt Chakram - 4-6 keys
Sky Blue Chakram - 5-7 keys
Burnt Sienna Chakram - 3-4 keys
Saffron Chakram - 4-5 keys
Lime Chakram - 4-6 keys
Forest Green Chakram - 5-7 keys
Orange Chakram - 4-6 keys
Purple Chakram - 4-7 keys


Painted Lightning

White Lightning - 15-17 keys
Grey Lightning - 10-12 keys
Crimson Lightning - 30-34 keys
Pink Lightning - 19-21 keys
Sky Blue Lightning - 15-17 keys
Burnt Sienna Lightning - 10-11 keys
Saffron Lightning - 12-14 keys
Lime Lightning - 14-17 keys
Forest Green Lightning - 14-17 keys
Orange Lightning - 13-15 keys
Purple Lightning - 17-19 keys


Painted Looper

White Looper - 14-18 keys
Black Looper - 6-9 keys
Crimson Looper - 17-19 keys
Pink Looper - 14-17 keys
Cobalt Looper - 6-8 keys
Sky Blue Looper - 13-16 keys
Burnt Sienna Looper - 7-8 keys
Saffron Looper - 9-13 keys
Lime Looper - 13-16 keys
Forest Green Looper - 14-16 keys
Orange Looper - 13-15 keys
Purple Looper - 13-15 keys



Painted Photon

White Photon - 10-13 keys
Black Photon - 4-7 keys
Grey Photon - 4-7 keys
Crimson Photon - 11-13 keys
Pink Photon - 10-13 keys
Cobalt Photon - 5-8 keys
Burnt Sienna Photon - 6-9 keys
Saffron Photon - 9-11 keys
Lime Photon - 9-12 keys
Forest Green Photon - 9-11 keys
Orange Photon - 9-12 keys
Purple Photon - 10-12 keys


Painted Discotheque

White Discotheque - 20-26 keys
Crimson Discotheque - 23-27 keys
Pink Discotheque - 19-23 keys
Cobalt Discotheque - 18-22 keys
Sky Blue Discotheque - 13-16 keys
Saffron Discotheque - 15-19 keys
Lime Discotheque - 15-19 keys
Forest Green Discotheque - 16-20 keys
Orange Discotheque - 19-22 keys
Purple Discotheque - 17-21 keys


Painted Lobo

White Lobo - 3-4 keys
Black Lobo - 2-3 keys
Grey Lobo - 2-3 keys
Pink Lobo - 3-4 keys
Cobalt Lobo - 4-5 keys
Sky Blue Lobo - 4-5 keys
Burnt Sienna Lobo - 2-3 keys
Saffron Lobo - 3-4 keys
Lime Lobo - 3-4 keys
Forest Green Lobo - 3-4 keys
Orange Lobo - 3-4 keys
Purple Lobo - 3-4 keys


Painted Pulsus

White Pulsus - 17-20 keys
Black Pulsus - 12-15 keys
Grey Pulsus - 8-11 keys
Crimson Pulsus - 19-23 keys
Sky Blue Pulsus - 11-13 keys
Pink Pulsus - 18-21 keys
Cobalt Pulsus - 15-17 keys
Burnt Sienna Pulsus - 10-13 keys
Saffron Pulsus - 13-15 keys
Lime Pulsus - 15-17 keys
Forest Green Pulsus - 16-18 keys
Orange Pulsus - 15-18 keys
Purple Pulsus - 16-18 keys
Trails
Crate Trails

Polygonal - 0.5 keys (Certified: 0.75-1 key)
Pixel Fire - 1 key (Certified: 1.5 keys)
Trinity - 1 key (Certified: 1.5 keys)
Hypernova - 1.5 keys (Certified: 2 keys)
Dark Matter - 2 keys (Certified: 2.5 keys)


Other trails

Hearts - 0.15 keys
Frostbite - 0.15 keys
Toon Smoke - 0.15 keys
Lightning - 0.15 keys
Ink - 0.50 keys
Treasure - 0.25 keys
Black Market
Slipstream - 9 keys (Certified: 10 keys)
Labyrinth - 7 keys (Certified: 8 keys)
Parallax - 11 keys (Certified: 12 keys)
Heatwave - 28-30 keys (Certified: 30-38 keys)
Animated Decals
Dominus: Snakeskin - 1 key

Breakout: Dot Matrix - 1 key
Breakout: Snakeskin - 0.5-1 key

Octane: Distorsion - 1 key
Octane: Dragon Lord - 0.5 keys
Octane: MG-88 - 0.5 keys

X-Devil: Snakeskin - 0.5 keys

Takumi: Distortion - 1 key
Takumi: Anubis - 0.5 keys

Merc: Warlock - 0.5 keys
Halloween Limited Items
Carriage - 1 key (Wheels)

Candy Corn - 1 key (Trail)
Netherworld - 1-2 keys (Trail)

Calavera - 0.5 keys (Antenna)
Fuzzy Brute - 0.5 keys (Antenna)
Fuzzy Vamp - 0.5 keys (Antenna)
Fuzzy Skull - 0.5 keys (Antenna)

Pumpkin - 0.5 keys (Topper)
Bone King - 0.5 keys (Topper)
Ghost - 0.5 keys (Topper)

Please note that Halloween items from 2015 are available again this season so their prices will become lower for few months
Christmas Limited Items
X-Mas - 1 key (Boost)

Candy Cane - 0.5 keys (Antenna)
Holiday Gift - 0.5 keys (Antenna)

Blitzen - 1 key (Topper)
Christmas Tree - 0.5 keys (Topper)
Sad Sapling - 0.5 keys (Topper)
Santa - 1-2 keys (Topper)
Alpha Items
Gold Nugget - 55-65 keys (Antenna)
Gold Cap - 100-120 keys (Topper)
Gold Rush - 350-380 keys (Boost)
Goldstone - 380-420 keys (Wheels)

Please note that alpha items' prices can be different since they are the rarest game in-game, so except the seller setting the price.
Certified Items
Tier 1

- Paragon (MVP's)
- Scorer (Goals Scored)
- Striker (Shots on goal)
- Victor (Wins)

Tier 2

- Aviator (Aerial Goals)
- Playmaker (Assists)
- Tactician (Centers)

Tier 3

- Acrobat (Bicycle Goals)
- Goalkeeper (Saves)
- Guardian (Epic Saves)
- Juggler (Juggles)
- Show-Off (Backwards Goals)
- Sniper (Long Goals)
- Sweeper (Clears)
- Turtle (Upside down goals)

Avoid getting tier 3 certified items since they value almost same as the base item.
Tier 1 certifications add 1-1.5 keys and tier 2 certifications add 0.5-1 key.