what
Xevyr said.
what
Para Handy said.
Expanded -
Be careful with those route planners. You want to watch the age of the prices:
Pad: M 107 ls 11 hours [might be OK] Pad: L 407 ls 3 days [not so good].
And even
then, they can be well off. Look at the SUPPLY on both ends of the route. If the price index says 10 hours, but the supply is high, that is worth checking. I've been flattened enough to know that a low supply isn't the best target, no matter
what the quoted price is. Have a look at the Traffic Report and News in the sector; watch for lots of Cutters and Anacondas [trading].
I don't know what your trade ship is; that can make a difference. If you can carry 400+t of something, it might make an easier route to take a small loss for a station near to jump-in point.
As Para said, 13 jumps is not a good route, unless it's a full bay of Rares. Ideally, a loop is 3-4 jumps at your max FSD. Some can be larger, but you must look over the pricing data - would it make more credits doing a short, 3-hop route than a much longer 4-5hop with further out stations? There are one-hop routes but they are mythical and happen
extremely rarely, so don't obsess over finding them. If they show up, it's a unicorn.
If you can afford a DBScout [ 500kcr new] and about
8mil for this A-rated build, [25ly] or perhaps a Cobra MkIII [350kcr new] and again,
about 8mil for this A-rated build [DBS jumps 2ly more but Cobra carries 36tons] do it. Unless it's a rock-stable thing that you've already been doing,
check your routes first, both ends, with a small, fast vessel and a test run. If you're trading in an Asp or something, just go to both stations first and check prices. Most of the time it's OK, but as you found, it can be a nasty surprise.
A good rule of thumb is
never fly without a cargo, even if it is only making you your fuel and docking fees. This is the Trader Creed. You might occasionally relax that if the 1-way trip is juicy enough to deadhead the way back. Even then, there's almost always
something you can take back.
A thing for me is that I do not often take stations further out than 700m; I just feel I get interdicted more times.
Some people will say, "do Imperial slaves." It's quite profitable. Depends on how you think about that kind of stuff.
My own trade explorations has shown me that getting certain medical items to systems in a war state can be even
more profitable, and usually everyone's too busy warring to interdict me lol. You
do know that you can filter the Galaxy Maps for systems states, yeah? On the edges of war or boom states & at the fringes; that's where you want to be trading.
Your ship should have
no guns, you don't need them and their weight. You're building for evasion, not fighting. Beef up thrusters, shields & boosters - you want to be able to run fast enough to get out of their range using Boost while your FSD spins up and you hi-wake.
Finally, remember that as you are using EDDB, so are hundreds/thousands of other Commanders!
Good luck, Trader