How about a Rotring 600 ballpoint pen - if you watch this pen on Amazon it will go down to $23 probably tomorrow. Seems the pencil is cheaper one day an the pen the next. It has a thin knurled grip which is easy to hold and a good click. It is my go to non-consumable/disposable ballpoint.

As far as fine point refills - having a pen that accepts Parker compatible refills means you can choose between regular ballpoint ink, hybrid ink and gel. Most, if not using a gel, go with hybrid ink like the Jetstream SXR-600 series and it comes as fine as 0.38mm. If you prefer needle tips OHTO make a 0.5mm Parker compatible gel, the flash dry.

Another choice would be to buy a Lamy Safari Rollerball - $16 and use Pilot G2 compatible refills. Pilot makes G2 refills as small as 0.38 in black as well as blue, red and green. Many more colors are available in 0.5mm and 0.7mm. Pentel Energel makes needle tip refills as small as 0.3mm and 0.4mm in black.

There is a very simple and easy mod to fit Pilot G2 refills into the Lamy Rollerballwhich is basically adding a small piece of plastic form the tip cover of a refill.

Although this is a capped pen, I use it all the time with Pentel Energel refills. IMO, this is the best gel refill.