Absolute cheapest are the Acer and Lenovo WMR headsets. Downsides are they use an LCD screen (colors not as nice, worse black levels), and they have a fixed IPD of 63mm (interpupillary distance, basically how far apart the lenses are so they are centered on your pupils). The IPD thing may be an issue for clarity if yours is much larger than this.
One step in price above that, your options are Rift and Vive. Advantages of those headsets is better tracking (WMR headsets use inside out tracking where the sensor cameras are in the headset rather in sensors you attach around your room) for roomscale stuff, but that isn't very relevant for sit-down games like ED. Another advantage is they use OLED screens, which provide better color and black levels. IPD is also adjustable. One down-side compared to WMR headsets, however, is that they use lower resolution screens (even compared to the Acer and Lenovo ones!). So it's a trade-off here between resolution and color levels.
There's also the higher end WMR headsets the Samsung Odyssey and Odyssey+. Probably the best commercial headset for Elite right now if you can swing it. Has OLED panels, adjustable IPD, and higher resolution than the Rift or Vive. The + version has an anti-screen door effect filter which apparently really reduces SDE.
Those are pretty much your main options. Keep in mind one factor I haven't discussed is comfort, and this is quite individual. Some people find one headset comfortable, while others do not.