May I ask some silly questions?

Are there prices involved in these races? Who gets them?
If yes, do they cover the training/transport/kit expenses?
Yes there are generally prizes/prize money. For nationals, generally no prize money is awarded, it is medals and the kudos. In open events, usually prize money, sometimes a trophy to the winner or some such. Club events, no prizes.
Usually to top few overall, top women, fastest team of 3 plus various vets or handicap prizes. Loads to be said about the allocation if prizes, esp with regards to gender.
The prize money generally is peanuts and would just about cover your entry and fuel if you are lucky and live quite close to where the race is held. For a distance race where nutritional requirements are high and racing tyres take a lot of wear (costing over £50 per tub and with lasting less than 1k miles, you can see how 100 mile/12HR/24HR TT's start costing you in this department), you are still racing at a massive loss. Equipment, coaching etc, not a chance prize money will make a dent in that.
Even sponsorship offers limited respite in terms of costs, you might get stuff, eg. Energy drinks sold to you at trade price in exchange for logos on kit, mentions on social media and submissions(pics, race reports etc) to the sponsors website for example. It helps but you are still spending.