Ikea's “Gerton” tabletop (90€ / $100. 155×75cm = 61×29.5”) is really, really nice — it uses ≈5cm-wide beech hardwood strips glued together and reinforced across the width with some metal . It works with Bekant legs (if you have a 10mm wood bit and some masking tape handy), which are also available as sit/stand legs (that's 430€ / $350, though. the non-adjustable ones are a lot cheaper.)

The hollow ones are a bargain until you try to attach a clamp on monitor stand or lamp. The clamp crushes the table top as you tighten it.