These ideas might not be a bad choice for one starting off
Taken from the absolutly huge collection of benches on the site lumberjock$
To find this huge collection of benches, prob over 200, type in to google...
All replies on Work bench smack down.
Edit: I forgot to add that you could find a "solid core" door, or what might be a smooth faced heavy fire door to a layman like myself,
to place on top of those simple sawhorses (with the interesting riser part added)
Two cheap f clamps to secure it to the "trestles" and the top butting up against something like a wall so it can withstand the lateral force of planing timbers.
Maybe another cheapie f clamp or two for clamping a batten for a planing stop, if not against a wall.
If the door, ahem,"top" would be bearing against a wall, then a few boards could also bear against the wall for planing against.
Adding another few of the larger heavy duty f clamps from Lidl also, will enable you to hold all kinds of stuff, instead of needing a vice straight away.
Should be enough to get you started from scratch.
Make a good enough second bench when you grow out of it.
Be compact enough to store away if you happen to stumble across a nice bench or make one later on, and are tight for space.
Here is another idea for a knockdown bench I thought was interesting
All the best
Tom