Get some -- and really get into! -- some spices. They are your huge force-multiplier when it comes to flavoring meals, especially on the cheap. Even if they cost $3 or $7 a pound, a small amount will last you so long and make such a huge difference that you won't notice the cost.
For your recipe, simply adding some chili powder would have added a load of flavor. You can get huge plastic jars of things like onion and garlic powder too at so many cheap supermarkets and food outlets for 3 or $5 a pound that you might as well indulge. It will take you months to get through them, and they will completely change your food experience. It's pretty fun to mix and match them, too, to see what you can come up with.
You can be more of a cook than you ever thought possible simply by fooling around with some cheap spices. If you want to take it to the next level, try caramelizing what you cook, too -- onions, veggies, meat ... instead of tossing it all in a stew pot or whatever, unbrowned. A little soy, worcestershire, even salt and pepper work truly massive wonders.
So what I'm saying is good for you if you find what you like, but ... if you want to experiment and take a shot at having much more fun with your meals and flavor in them, play around with spices. I grew up knowing nothing about spices outside salt and pepper. Once I learned how huge a difference a spice or too could make, I felt like I had been robbed of flavor all my life! And joy!
Don't think that even with just a little money you have to "make do" with whatever flavors you have. You don't have to keep to what you've got, or settle for less, when even a teaspoon of herbs or spices can turn your whole eating experience around and make you a better cook and happier eater than you've ever been before.
I'd just recommend ... have courage! Be positive! And go spend just a little bit to have some fun with your food and your creativity and increase the WOW! factor of your life a bit.
I swear you'll love the results -- and probably yourself a little more -- if you experiment around a little and just try. If you're worried, don't be. It's almost never as expensive to try everyday common spices as you think ... and even some weird ones you've never heard of.
Be brave! Be happy! Smile! And go drop a dollar for some herb or spice you've never heard of.