Tokens, in general, are not the same as shares in that they do not provide ownership stake or voting rights in the corporation. Typically, they are simply vehicles with which to conduct transactions for the goods or services within the corporate entity from which they are issued. After the ICO where the company sets the price for the tokens, their value is based on supply and demand. Demand is usually speculative and created by people's perception of what they think the particular corporation's importance will be in this new, rapidly evolving, yet very powerful world of blockchain technology. This speculative nature, as well as the fact that tokens provide no form of ownership, is what has led many established traditional Wall Street corporate investors to call this new investment vehicle dangerous, fraudulent, Ponzi-like, a big "bubble", etc. There's no doubt that many of the companies issuing cryptocurrency tokens will disappear in time leaving their tokens worthless, but there is also good reason to believe the best ones will become large, powerful, and ubiquitous in our future. The tokens, which by the way are usually finite in number, of the surviving companies in this nascent cryto-world will have more value as the demand for their use increases. Some people will buy and hold the tokens as stores of value while others will actively use the tokens for the goods and/or services of the company. Usually tokens are traded on established exchanges such as Coinbase, Kraken, Poloniex, etc. that connect buyer and seller but every exchange decides with which coins they want to deal. Due diligence of a company should be performed before deciding to which ICO's one should "contribute" (the term used to buy tokens in an ICO) just as one would when buying a traditional stock.
Think of tokens like concert tickets. You don't buy ownership in the band, but need the ticket to consume (see) the band. Tickets can be bought and sold and their value depends on the popularity of the band/demand to see the band. There are exchanges, like StubHub, that facilitate buying and selling. There are limited numbers of tickets just like there are a finite number of tokens. An ICO would be like prepurchasing tickets for future concerts at a very low cost. The band may or may not be around in the future but if you can spot the diamond in the rough, your tickets could be very valuable in the future. If you prepurchase tickets to a band that goes nowhere, you lose everything.