> Of planets without purchasing another telescope or different lenses. If not, what are some better telescopes (on the cheaper side) or lenses that I could possibly purchase for my current telescope?
The cheapest scope I recommend is the Zhumell Z130 or Heritage 130p/AWB OneSky. They normally go for $200 in the US. Any cheaper and it's not worth it.
As far as getting the most of your scope, You will want a reasonable quality 7mm or 8mm eyepiece to get you something approaching planetary magnification (7mm = 100x, 8mm = 87.5x). The view will be dim, and will have some strong chromatic aberration, but that's the best you will be able to do in this scope.
You don't want to get a Plossl for focal lengths this short. It will be too hard to look through. Instead, I recommend one of the following:
The 7mm Celestron X-Cel is expensive and a bit overkill for your telescope, BUT it's a quality eyepiece that will probably work nicely with a future telescope upgrade.
I also agree with /u/DrakonisZA that you may need to upgrade your diagonal. The stock ones that come with Meade scopes are typically a weak link. But start with the eyepiece first, make sure to wait for the planet to be as high in the sky as possible, don't observe from indoors or directly over rooftops, and be patient for steady atmospheric conditions.