Cheap tweaks...What would YOU reccomend?

Bass traps! I guess these could be fairly expensive if you really go all-out but even one or two strategically placed traps can make an amazing improvement.

For anyone using oriental screens:

I used an oriental screen at the back of my room to diffuse a nasty flutter echo. I eventually realized that it was resonating at a bunch of different frequencies and creating large peaks in the frequency response that I had previously attributed to poor room dimensions.

I found that filling each compartment in the screens with sand helped immensely. My screens had six panels and each panel had 7 compartments. I drilled into each compartment at the edge of the screen (and on the edge that faced away from the front) and used a funnel to get the sand in. It was hard to avoid clogging so this process took some time. However, it decreased the resonance and even seems to have prduced some bass trap effect. Smoothed the room response right out and made everything tighter in the process.