Decent clothes. Go to decathlon and buy some pairs of bib shorts and some jerseys, 500 series, ideally 700. Shoes if you want to ride clipless, otherwise make do with trainers on flat pedals. Bottles, but they're dead cheap. Multi tool and puncture repair kit and mini pump. You can live without a computer for a long time, but they are money well spent in time.
Eyewear is tricky. If you can't see without them, then glasses are essential. However, they're also important for protection from stones or whatever gets kicked up, so you may not want to use your regular glasses for that! You can get prescription eyewear, but obviously that's pricey.
Eyewear is tricky. If you can't see without them, then glasses are essential. However, they're also important for protection from stones or whatever gets kicked up, so you may not want to use your regular glasses for that! You can get prescription eyewear, but obviously that's pricey.