The Warhammer historical section is having a halfprice sale. This is fantastic value as the rulebooks (now $15 each) are also only $5 shipping worldwide. Even at full price at $30 they are very good quality productions - my Legends of the Old West is one of the best-presented and well laid out rulebooks I own, with great quality, illustrations and lots of 'wow factor'.
For those unfamiliar with Warhammer Historical, they offer historical versions of GWs Lord of the Rings and 40k rules. These rules are far better rulesets than the originals and have excellent campaign systems a la Mordhiem.
Their Legends of the High Seas pirate skirmish rules include ship combat and I have ordered this and a copy of their Trafalgar naval rules which should integrate well. Although often derided by Age of Sail 'purists' Trafalgar is apparently much simpler than the often 'beardy' overcomplicated age of sail rules. It is similar to the excellent Battlefleet Gothic rules (IMO up there with Space Hulk, Epic and Bloodbowl as one of GWs few decent games) so I am looking forward to my ruleset. I will compare it to my Cutlass! rules when I get my Black Scorpion pirates painted up.
I own Legends of the Old West (cowboys) and have just ordered the "Blood on the Plains" and "Showdown" supplements.
If you are familiar with GW's LOTR skirmish you know the basic mechanics. They use a modified IGOUGO sequence, where Side A moves, then Side B moves, then Side A fires, then Side B fires. It's still simple, but mitigates many flaws of the IGOUGO system.
Heroes can interrupt and move and fire out of sequence at they use up their 'Might' points. Heroes can also activate and affect friendlies within a certain radius of themselves. Heroes can also use 'Fate' points to cheat death, using it to roll to save wounds. Heroes have usually varying amounts of Might or Fate (usually 1-3) and managing this resource is very important. Unlike 40k, they seldom possess monster stat lines; they simply use their Will and Fate to influence the battle and pull off heroic feats rather than being an unstoppable monster that can kill entire squads single-handed.
Campaign Rules OK
These are not the most complex rules and they lack a 'reaction' or 'overwatch' system that I prefer in skirmish games, but the rules are slicker, smoother and more 'tactical' than 40k. The star of the show is the campaign rules. You can start your own band of gunslingers, lawmen, bandits or indians and have them progress from a humble cowpoke to, well, a "Legend of the West."
More than simply what you get in the box
In addition, there are numerous free Legends supplements covering different eras - for example I have downloaded the free Legends of the Rising Sun samurai mod to use with my Perry samurai warbands.
In short - great value for what you get - well worth snagging a copy.
PS: They also do WW1 and WW2 books and a set of "gladiator" rules that look interesting....