This one can get a bit messy, so really it's best to only sum it up here in a rather basic way. I urge you to go Google the ins and outs of all this.
Usually a coin is a crypto designed to act as a form of money, means of value transfer, and that's it. i.e. Bitcoin and Litecoin to name but two.
Tokens are typically built on top of another blockchain such as Ethereum, like ERC20 tokes for instance. These tokens can act as a form of money and a means of transfer, but I that's not their real primary purpose. The main purpose is to act as a means of transacting within the dApp (decentralised application) or ecosystem of that project. Think of it like buying tokens at a fairground. You pay your money (dollars and cents) and get a handful of tokens in return to put into the machine that starts the rides. But in this case the token is used to pay to use a service like the dApp I mentioned.
One such example is the Theta token. Theta have a project surrounding decentralised video streaming. When it goes live, and if you choose to take part, you can either earn Theta tokens by renting our your bandwidth and personal computer processing power to others in your area to make video streaming smoother for them, or pay to receive streaming services by using your own Theta tokens. FYI : Theta was built on ETH as an ERC20 token originally but moved to it's own blockchain fairly recently.
Secondly there's projects like Digitex which was also built on the ETH blockchain as an ERC20 token. DGTX plans to build a Bitcoin futures trading exchange platform, but you have to buy the BTC futures contracts on their platform using DGTX tokens. You must first own some DGTX tokens before you can do anything on their platform, like the fairground example. No tokens ... no rides, because the rides don't accept anything other than the official fairground tokens you buy at the entrance gate.
Compare these two examples to BTC and you can see the difference. BTC was only ever designed to be digital dollars and cents. i.e. a way for me to send you $100 (or however much) quickly and easily peer-to-peer with no middle man. That's it's one and only purpose.
Of course I could also send you $100 of Theta tokens to settle a bill between us both, but that's a side issue. That's like saying I could either give you a $100 bill or $100 worth of potatoes. Same thing and all fine as long as you want $100 worth of potatoes.
Sadly it's not an easy thing to sum up quickly, so please do some further online reading to clear up the quirks of all this.
