Understanding Different Types of Online Slot Machines

We'd be wasting your time if we attempted to categorize all the types of slot machines. Every casino offers a wide range of slots to attract gamblers. Slots come in hundreds of types and variations, from single line and 3 line, to 3 or 5 reel, and from bonus games to progressives, to mention just some.
It makes more sense to look at the typical characteristics of slot machines.
Number of Reels
There are usually 3 or 5 reels in a slot machine. Early slots had only three reels. We remember them as "classic" or "regular" machines.
Today, 5 reel slots are common, and they generally feature more than one payline (see below).
Number of Rows
Slots machines feature one, two or several horizontal rows marking positions on the vertical reels.
Extra rows, usually one above and one below the payout display, tempt players with a view of how narrowly they might have missed a win.
Number of Pay Lines
There can be one or more paylines crossing the reels. It's common to see 3, 5, 9, 15 and more recently even 20 lines. For a winning combination, the designated symbols must fall on a line, often the central horizontal line.
There's only one payline crossing the three reels on a classic machine. You can bet one or more coins per spin but only the center line pays, and increasing your bet doesn't improve your chances of winning.
On a slot with more than one payline, you can bring additional lines into play by upping the number of coins you play. You don't have to bet on every available payline.
Suppose you're on a 3 line slot and you're required to insert one coin to play the center line, a second coin to play the line above center and a third coin to play the line below center. If you now bet only one coin and the reels display a winning combination on the line above or below the center, you don't win anything because you played too few coins.
By offering diagonal matches, slots with 5 reels can have from 5 to 20 paylines.
Denomination of one coin
There are slot machines which accept denominations from as little as 5 cents to $5. High roller slots may accept "coins" with a denomination of as much as $500, although these are few and far between. Some online casinos have special limits set up for their big players to accommodate large bets..
Number of coins that can be played
The maximum bet on classic slots is usually three coins, but there are some slots that accept a 2-coin maximum bet. Again, video slots have changed this characteristic dramatically, with some multi line video slots now accepting up to 10 coins per line.