The only pens I have that have snap on caps are my Pilot Metropolitan and Platinum Preppy.
As
@HMan mentioned, Platinum has a cap system that puts a real good seal on the pen. I’ve converted my Preppy to an eyedropper but use it sporadically. It can sometimes sit for weeks without use but never has issues when I go to write with it. The only issue I had with hard starts was when I had a high sheen ink in it, but that was an ink issue not a pen issue.
As far as snap over screw caps, it’s really just preference. TWSBI also has a very good cap sealing system, and the ECO and Classic come off with one and a half rotations of the cap. My Moonman is about 3 rotations. Again, all preference.
if you’re looking for low price options on a nice screw cap pen, TWSBI’s Eco’s are awesome in my opinion. For just under $30 you can get a demonstrator with a piston fill system. Nemosine pens are super cheap and I love my stub nib Singularity (after they replaced the defective feed/nib for me). Their stuff is all clearance right now, so you’re looking at about $10-15 with shipping. I believe Birmingham Pens are somehow related to Nemosine and are very cheap as well.
The Moonman I just picked up is a real winner. Under $20. Beautiful resin pen. Super smooth nib out of the box. The biggest complaint I hear about them is that they rip off a lot of other companies designs. the model I picked up is their version of a Pelikan M600. If you’re ok with that, these are excellent pens on the low end of the price spectrum, which is where I tend to stay myself.