There tends to be two schools of thought. Some people start off with one or two repair items and end up using a box trailer as a flight box, others start off taking everything and slowly reduce it to the bare necessities. How close the hobby shop is to your flying field and the days it's open will have a big impact on what you bring too, as will your skill level (the number of crashes you have tends to reduce as your skills improve). I prefer to rely on good at-home maintenance and keep the on-field spares down to a spare prop, a roll of clear packing tape, and a length of fuel line. You'll find that'll get you out of most minor scrapes at the field if you're creative (eg: some tape around the end of the axle can be a make-shift wheel collar for a flight or two), and anything requiring a more exotic repair is best done at home. For a beginner I might include some wheel collars, maybe some rubber bands (even if your wings bolt on they're still useful at times), a small bag of assorted screws, and a bottle of thin CA but your best friend is really at home maintenance.

Go over your planes with a fine tooth comb before and after every day's flying, make sure all the grub screws have a drop of CA or locktite, the muffler screws too, wheels turn freely, prop nut is tight, batteries are charged and reliable etc... make it part of your end-of-day ritual while you're cleaning the plane off (assuming it's glow). Most field repairs for beginners are due to something coming loose, crash damage is usually not field repairable regardless of how many spares you have.