i started bicycling-as-a-hobby as a cliched broke college student, now i have titaniums parts and wool jerseys and helmet liners and arm warmers and co2 pumps and other doodads.

they are all frill.

what is essential, for hobbyists, is to have:
-home pump
-few spare tubes + patch kit
-allen toolset (really, you only need about 3 sizes)
-lube
-blinkies

niceties:
-saddle bag
-computer

the rest, stock up incrementally as your interest and budget allows