Not a bad price, though it seems things are a bit more expensive across the pond than they are here. As for ships...
You just can't go wrong getting the ships you love. Most ships are at least somewhat viable depending on the squad they have with them, and all of the upgrade cards are available through a number of phone apps and squad builders online if you want to just copy things out/print them off and play whatever builds you like. Can't say I know anyone outside of maybe a tournament setting that this isn't fine with.
The Falcon is a beast in the game provided you play whichever pilot (Han and Chewie are my go-to's) you like with a bunch of upgrades, and a T-70 or two would go great with it.
I've...never really liked the Firespray as an Empire ship. It came out likely before they figured they'd be adding Scum and Villainy, but really I haven't seen it used as an Imperial ship more effectively than as a Scum ship. This does however mean you need Most Wanted. As for Scum and the Empire joining forces...I could break the game pretty damn easy by taking pilots from across Factions like that. Do whatever you like in a friendly game of course, but it isn't something I would really consider. I have a ton of ships and each group plays so very differently to me now that crossovers are almost jarring to my feeble mind :laugh:
As for essential purchases....well, that really depends on whether you're able to print off/play with homemade cards so you don't have to buy ships just for upgrades to make the ships you actually like better (like getting Autothrusters for your Interceptors out of the Starviper pack then never using the Starviper because it's not a ship you're truly interested in). If you're cool with using whatever for upgrades then I would honestly say buy whatever makes your inner fanboy happy. I can come up with decently competitive builds out of just about anything, heck I won a game last night with three T-65 X-Wings; a ship most people say is basically useless despite being the namesake of the game.