You don't need that many special tools for day to day work on the bikes. A decent toolkit with sockets, spanners and allen keys will do most of the work. The clutch tool is quite cheap to buy but people have made them from wide screwdrivers or chisels. One tool you may need is a clutch basket holding tool, this can be made from an old alloy plate, bolts and some bar or box section metal to form a handle. You only need this when removing the clutch basket to change the bearing in it or the countershaft bearings.
Depending on the carb on the bike you may need a setting gauge and dial to get the settings correct, ideally for a first bike a simpler carb like a Finn Jensen would be ideal as these only require simple maintenance unlike Blixt which require more stripping and the special setting gauge.
As for parts breaking it depends how often and how hard you come off! Primary chain guards are prone to damage as the bike normally comes down on that side and slides along it. A lot of stuff bends before it breaks like rear pushbars which can be persuaded back straight. If the frame or forks get damaged these can be stripped off the bike and usually straightened. I have seen some properly banana shaped bikes that have been straightened. This can be done at places like JHR in Swadlincote near Derby. You can go a whole season without breaking anything but you can go event to event and break something similar to trials really!