Black
Red
Odds
Even
High Numbers
Low Numbers

All of these bets pay 1:1 (ie evens). In other words if you bet $1 you will win $1 back plus retain the $1 bet. The profit you make on a sucessful bet will exactly match your bet size.

Even money shots - what are the actual odds

European Roulette Wheel (one zero) with La Partage Rule: 18.5:19 giving the casino an edge of 0.5/37 (1.35%)
European Roulette Wheel (one zero) without La Partage Rule: 18:19 giving the casino an edge of 1/37 (2.7%)
American Roulette Wheel (two zeros): with La Partage Rule: 19:20 giving the casino an edge of 1/38 (2.63%)
American Roulette Wheel (two zeros): without La Partage Rule 18:20 giving the casino an edge of 2/38 (5.26%)

(The La Partage Rule is where you get half your money back on even money bets if the ball lands on zero)

2:1 shots - what gets paid

Numbers 1-12
Numbers 13-24
Numbers 25-36
1 Column
2 Column
3 Column

All of these bets pay 2:1. In other words if you bet $1 you will win $2 back plus retain the $1 bet. Basically profit of 2 times the bet

2:1 shots - what are the actual odds

European Wheel (one zero): 12:37 giving the casino an edge of 1:37 (2.7%)
American Wheel (two zeros): 12:38 giving the casino an edge of 2:38 (5.26%)

Double Street (6 numbers, eg 1-6, 7-12)

Usually pays 5:1. In other words bet $1 and get $5+$1 back ($5 profit). Similar to the 2:1 shots the casino is paying the actual odds as if the zeros werent present, so the house edges once again are 2.7% on the European Wheel and 5.26% on the American Wheel

Corners (4 numbers eg 7,8,10,11 ("the 7-11 corner"))

Usually pays 8:1. In other words bet $1 and get $8+$1 back ($8 profit). Again for the same reasons as above its 2.7% house edge on a corner bet 5.26% house edge on a corner bet, dependant on the wheel

Streets (3 numbers)

Usually pays 11:1. In other words bet $1 and get $11+$1 back ($11 profit). Again for the same reasons its 2.7% house edge on a street bet or 5.26% house edge on a street bet, dependant on the wheel

Splits (2 numbers)

Usually pays 17:1. In other words bet $1 and get $17+$1 back ($17 profit). Again for the same reasons its 2.7% house edge on a Split or 5.26% house edge on a Split, dependant on the wheel

Straight-up (1 number)

Usually pays 35:1. In other words bet $1 and get $35+$1 back ($35 profit). Again for the same reasons its 2.7% house edge on a straight-up or 5.26% house edge on a straight-up, dependant on the wheel

As you can see all bets from 2:1 shots down to Straight-up bets are standard on the house edge. On all of them you get paid the actual true odds as if the wheel had no zeros.

There is another bet (which should be avoided) because it isnt neatly divisable by 36. That is the bet of first 5 numbers on an American Wheel (the zeros and 1,2,3). Because 5 doesnt go into 36 exactly the house ends up paying 6:1 instead of 6.2:1. On this bet the house edge therefore becomes 3/38 (7.89%)

Summary

As you can see you really should be looking to play your online roulette on a European Roulette wheel (single zero) in order to minimize the house edge. If you want to play on a European Roulette wheel then Give Ladbrokes Casino a go which includes an excellent 100% bonus (and even £50 free for UK players).