Well, I just did a search on dealtime, mysimon and ebay. Apparently, if you want a new TiVo unit, the only way you're going to get in that price range is to sign up for directtv on Amazon or buy one on ebay. Used units can go down to $149, but you may not get a warranty.
So, yes, there is a way to get the cost down on a TiVo to compare it to a replay.
I have a TiVo and a bunch of replays. I adore my Replays, and the TiVo bothers me so it sits in a room I never use and records stuff I would never watch. My husband likes the little cartoon tv on it, though, so I keep it.
You should see if you can get someone to show you the difference in feel between the units. Some people love their TiVos, and some people love their Replays. There's definitely room for both in the market since they do such different things.
Just recently I found myself explaining the bare difference between TiVo and Replay to a friend who is considering buying one. Basically, I got it down to: The TiVo can do lots of stuff if you put in the effort to hack it, but the Replay does its cool stuff out of the box.
One thing that is similar between the two that no one really brings up is that Replay has something very close to TiVo's random show picking. If you set up a Replay Zone, and you find that you like a show it grabs, you can set up a channel for that show, like a thumbs up. You can guarantee the channel, like a double thumbs up. You can then set it to record all shows, like a triple thumbs up. With zones, it still picks random shows based on your preferences, but you know what kind of things you're going to get, and when it finds something you really like, you can stick with it.
So really Gerry, get the machine that does what you want it to do. A Replay is (in my opinion) very close to a VCR as far as controlling it goes, and much easier to use. The TiVo has many menus to slog through to get to the record screens and to what you've recorded. But YOU should make your decision on what to get based on your own criteria, not anyone else's.