I go to Vegas about every 2 months, sometimes more frequent. To get the really good rates, you have to sign up for their card membership programs. They'll email or send you flyers about special rates/deals they have going on.
Personally, I would never stay at the Excalibur, especially at $195.00. That's a kid's hotel. Same thing with Circus Circus. Excalibur is better than Circus Circus, but generally you can find a higher quality hotel for the same price or not much more.
If you want the most savings, go on a weekday. Weekends are way too packed and being that you're in SoCal, everybody and their mama heads out that way. I find that I can enjoy a lot more on the weekdays, from gambling to the buffet line. The only benefit I see about weekends is if you like big crowds or you like clubbing. For me it's not worth the price premium. The first time I was in Vegas, it was on a 3 day President's holiday weekend (which I didn't realize until we got there) and we only had a room booked for Fri, figuring we'd be able to easily find another room for Sat night. I ended up paying $400 for a regular room at the Flamingo, a room that would normally go for less than $100 on a weekday.
You might want to look into some of the off-strip hotels if you're looking to spend the least amount of money. One I like is The Orleans. I've stayed their on weekdays for as little as $30/night and it's a nice, large room for what you pay, compared to some of the other hotels on the strip. Generally, their prices will range between $45-60 on a week night The only complaint I have is that the inside of the hotel is a lot "smokier" than higher end hotels on the strip, which seems to have better ventilation systems/air cleaners. It's off strip, but still close enough by car/cab.
The Orleans is part of the Coast Hotels and IMO, they offer some of the best rates in Vegas for very nice rooms. If you want to be further from the Strip, you might want to check out the Suncoast which is in Summerlin, a suburb of Vegas. The Suncoast also has a nice looking golf course (I don't play golf though) and it's near the new Red Rock Hotel & Casino. I like to escape the ghettoness of SoCal so Summerlin fits the bill nicely. It reminds me a lot of Rancho Mirage near Palm Springs. If you have your car with you, I would suggest driving around and exploring the rest of what Vegas has to offer. Even without a navigation system in your car, it's fairly easy to get around once you get familiar with some of the main roads. If you stick to the main road, you'll be able to find most places you want to find eventually.
As far as Fremont St., it's an interesting place to go but besides the Golden Nugget, everything looks old and shabby there. Even the rooms at the Golden Nugget are way smaller than the usual rooms around Vegas. Generally speaking, you'll run into a poorer crowd in downtown and it's a far cab ride if you're planning on going to the strip.
Some of the rates there are cheap, but I still think you get a better bang for your buck off the strip at some of the Coast or Stations Hotels/Casinos.
As far as hotels on the Strip, I generally get some of the best rates from The Aladdin now known as Planet Hollywood. Their weekday member's rates can be as low as $49-89 and I would say that it's about a 3.5/4 star hotel out of 5. I like the layout of the hotel because you can check in and go straight up to your room without having to walk through the smokey casino floor. Unfortunately the last few times I was there there were always constant renovations going on, and so I was a bit annoyed with how everything was moved around or shut down.
BTW, good luck finding a table with $5 or $10 minimum bets on the strip. It's next to impossible. Even if they had some, it'll be 2 tables at most and it's always filled up. $15 seems to be the new $10 in Vegas. If you stay off the strip, it'll be easier to find $5 tables but even that's becoming more rare nowadays.