In those days, the answer was usually, "Not much" (though since I was a salesman, I rarely put it that way). Today, I'd be able to reply enthusiastically, "How 'bout 100 watts times six channels, Dolby Digital EX and DTS-ES decoding, Pro Logic II and Neo:6 surround processing, component-video switching, and a six-channel input for DVD-Audio and Super Audio CD?" And I wouldn't be blowing smoke either, because $300 will buy you all that and more.
You can reap these affordable marvels from any number of manufacturers, and we picked three of the newest entry-level A/V receivers to represent their generation: the Onkyo TX-SR501, Panasonic's SA-XR25S, and the Yamaha RX-V440 - all $300 list. Judging from these three, "entry-level" hardly means stripped down nowadays. These babies bring more to the table than any previous budget-price receivers I've tested.
So what don't you get for your $300 compared with, say, the more upscale A/V receivers out there? Well, you don't get the heftiest chassis in the world. You also give up a fair amount of input and output flexibility. For example, none of these receivers includes preamp outputs for the main channels. And at these prices, you don't get extravagant features like extensive multiroom abilities and elaborate touchscreen remote controls.
You also don't get much in the way of FM radio finesse. All three receivers had only fair weak-signal abilities, and they tended to overload on very strong local stations, with audible effects or "popping through" over weak adjacent signals (or both). But so what? In the critical tasks of multichannel amplifying and surround sound processing, each receiver was more than competent. PDF: Features and Specs