I use the Asp, it'll cost you a lot to upgrade it to a usable state! My strategy is this,because I have less cargo capacity than the type 6 I do a bit of bounty hunting in between runs. It's not all about credits, you must try and enjoy the game to

if you just think about gaining credits all the time what's going to happen once you have the largest ship available?
So...find your trade route, fill up with cargo at one end,hit a nav point on route back to your final destination and have a shoot fest for as long or as short a time as you see fit! finish that drop off your cargo and repeat! Back home for tea and medals!
Sometimes I get 250,000 credits or more per session bounty hunting but it makes everything more exciting knowing that I risk losing over a million credits in slaves or palladium

even paying for damage and ammo doesn't bother me anymore

Just remember to keep your insurance as back up!
When I had the Type 6 it was just grind grind and a bit more grinding got enough for the asp, bought it and thought I'd made a massive mistake! but give it time, get some weapons and a few select upgrades and get back to enjoying the game again!
The Asp is like a big cobra with knobs on! If grinding credits is your game then don't get the Asp stick with the type 6 and be a space trucker!