At present all but essential travel is still off the cards and people have been tried to avoid using public transport if at all possible. This is because it is very hard to social distance on trains and buses especially until they have had time to change the layouts to allow for this.
Prior to lockdown more and more people were using public transport as there were more routes added and journey times were faster. It is also seen as a more environmentally friendly way to travel. Sometimes you may find the cost of a train ride to your chosen destination is more less than it would cost in fuel and parking if you were to go in your own car and also it saves wear and tear on your vehicle.
If you are looking for cheap train tickets then you may want to research prices on a number of different sites to find the best option. Some places even offer discounted train tickets if you are visiting them such as Cadburys World or Disney Land Paris.
It may be that two single tickets works out cheaper than buying a return and often off peak tickets offer a saving over peak tickets, so just by altering your travel time you can save quite a bit.
Booking your train travel tickets in advance can also be a way to save money as well as booking tickets at the last minute.