For cheap gambling, go for blackjack. Slots are boring. Blackjack is fun, and the house advantage is low (though you will lose in the long run). Plus you get to chat with other players at the table as well as the dealer while you play. Also most places will give you free drinks as long as you sit at the table for at least 20 minutes or so. Remember to tip the drink server a buck or so each time. Also tip the dealer a buck or two when you hit a blackjack.
Find a lower end casino - last time I was in Vegas (about a year ago) you could still find $10 min bet tables at most of the mid to low casinos, especially during daytime hours. This is about as low as it goes in Vegas these days.
Look up a Blackjack table, and try to get it down. You can certainly play without one, but you’ll swing harder. Most of the main casinos won’t allow surrenders, so keep that in mind.
Nearly every place raises table limits when night comes (usually 6-7 PM, IIRC). However - if you sat down at 4 PM and they raise the limits at 6 PM, every casino I have ever been at will allow you to keep betting at the 4 PM limits. The pit boss loves you if you have been sitting there for two hours.
Remember - luck comes and goes. Playing optimally you can lose ten hands in a row. Playing as a complete neo you can win big. I like Blackjack because swings usually aren’t that big - sure, the house will win every time in the long term, but you can certainly swing for a while, enjoy some nice conversation, have a few free drinks, and feel perfectly compensated for a few hours of entertainment.
Of course, you can also be running hot, hit a couple of lucky hands, and win a few hundred dollars. Or run cold, lose ten in a row, and bust within 20 minutes. That’s why it’s gambling.
If you’re up for some nature, I highly recommend hiking or driving Red Rock Canyon or Valley of Fire. Both are parks not far from Vegas. Gorgeous desert scenery, which for this midwesterner, were absolutely breathtaking. Plus nothing cures a mild hangover like a late morning walk through a perfectly silent desert park.