I think most people will have a favourite Classic car, perhaps a Hillman Imp or Singer Chamois, except for those that simply buy Classic Cars because either they just like collecting them or they are an investment. For those of us who simply buy a Hillman Imp or Singer Chamois because we like it, then usually our first car, or the car we first took our girlfriend out for a drive in, or even, the car we passed our driving test in will be the car we buy and restore in the future. It doesn't have to have been a Hillman Imp or Singer Chamois but I included those because they were two of my favourite classic cars.
No matter which car is your favourite, Hillman Imp or Singer Chamois, buying one can come down to either you have some spare cash and see one, perhaps on eBay, or you just see one driving down the street and it brings back such fond memories. But can you get one at the right price? Of course you can, just take a look at eBay, filled with cars. Do you have the knowledge to repair it or restore it? Some websites will give you tons of information on what to do, club websites will have plenty of members on hand to give advice but if you are not comfortable doing it yourself, seek advice, especially from the club members on good reliable garages or mechanics that they can recommend. You can also find good Classic Car Article websites filled with advice on restoration, where to find parts etc. etc.
Finding the club websites is not always as easy as it appears, google it and it may come up but you can also use Classic Car directory websites to find relevant sites for you.
At the end of the day, get the car you want, do to it what you want and simply enjoy it!