Can I be a total PITA and suggest the core Savage Worlds RPG book? It's Called the Save Worlds Deluxe Explorer's Edition, and only costs £7 for a small format softback. There's also a fairly decent starter PDF called Test Drive on the Pinnacle website.
The game basically rates you in five stats and fifteen skills, from D4 to D12 (roll 4+ for a basic success). Characters also roll an extra "wild die" (a D6) to give you a second chance at success. There are many Edges and Hinderances to customise your character, so a broadsword-wielding Paladin feels very different from a rapier-wielding Swashbuckler. Basic rules cover everything from a club and shield to power armour and lasers, and has a small selection of "typical" roleplaying monsters. It plays fast and pulpy with minimal book-keeping.
The "Effects" system is a single set of special abilities that covers spells, psionics, weird science - anything out the ordinary. There's a decent vehicles selection, and a small section on running squads for mass battle.
The core rules have everything you need, but there are genre expansion books for Fantasy, SciFi, Horror and Supers. The SF one goes into world and animal creation, hacking and cybernetics, more vehicles and a host of sample NPCs, beasties, robots and the like.
There are also dozens of setting books, which contain many adventure seeds and campaign outlines.
The one thing it's lacking is points costs - there was a builder tool out there, not sure if it still exists.