This site allows you to search by price and brand. They also have excellent customer service and good ink and paper options. I recommend them highly, and they've had far too much of my money over the years:
https://www.gouletpens.com/collecti...ng&filter.v.price.gte=&filter.v.price.lte=100
Specific models to explore:
Pilot Metropolitan - about $25, will last forever if cared for. Cartridge pens
Pilot Prera - about $60. Cartridge pens.
Lamy Safari or AL-star - maybe $30-60 based on materials. Cartridge pens.
TWSBI 580 / Vac700R / ECO / Precision - $20-100. Usually piston or vac fill, so bottled ink required.
For a first fountain pen, I'd maybe lean towards cartridge converters. A bit less maintenance, although less ink. Up to you though.