Sadly ED in game tools are lacking in certain and various areas. Hence we help ourselves with 3rd party tools, which interestingly, are at least acknowledged by FDEVs themselves. (Fun or sad note - FDEVs stated at some point that they are unwilling to create/update in game tools since 3rd party ones cover that area well).
Anyway, two major links for such tools:
eddb.io
On main page click "Stations" and there, under "filter" add ship you're looking for. Lower, in "reference system" put your current location. Now "find stations". In the table below you'll get list of all nearest stations that offer said ship.
This way you can find not only ships but modules, you can search for certain factions, powers, economy. With EDDB you can find profitable trade routes or trade loops, you can pin point resources, etc. Just play with different options and filters.
The other main tool is already mentioned Inara.cz. I advise you to make an account there - with it you can upload your ED profile and kepp trak of everything you have - ships, modules, credit balance, assets, engineering as well as it contains neat database of systems, stations, commodities, engineering and many more.
YOu can also set yourself financial goals which will give you an estimate on how long it will take to reach them, based on your activity and income rates. Pretty handy tool.
There are many more external tools that help with ED but are more specialized, those two above are the most general and for everything in the beginning.