I'm thinking about pure-wifi repeaters lately. I came home for Christmas and my dad had gotten himself one of these:
It's pretty neat. $45 and it has a battery and a special "wifi hotspot" mode, specially designed (supposedly) to deal with wifi hotspots that need stupid login pages. The idea is you can use it in a hotel room and all your devices and share a single link to hotel wifi.
Now okay, I haven't validated the hotspot feature (they don't have a stupid login pages at my parents' place) and their UI is pretty awful and buggy. But I like the idea and I like the price. And it really does boost wifi signal strength when used appropriately.
Mind you they only have a 4 Mbit/sec Internet link here. Repeaters use your wifi bandwidth pretty inefficiently, but you have a long way to go before 150 or 300 Mbit/sec gets all the way down to 4.