Here are some pictures of a Roper monster I made for D&D, I did have loads of "in progress" photo's but because my phone died on holiday I lost all the pictures I had taken.
I used the following materials.
Base and basic Roper shape from Cat food box card
Tentacles from green gardening wire
Eye, mouth and teeth (also some small sections on the tentacles, ends mainly) from GS
PVAcrete applied over most of the model to give it a rock like feel.
I didn't have to buy a thing for this build at all.
Also coated the whole model in Antique Oak varnish as usual.
They are a funny creature visually and while not my favourite looking, they are very nasty in combat.
To give an idea of scale I have added in a few wood elf archers and a Satyr.
He's been used in one game already and will feature again in the future.
Looking at making a whole range of nasty gribblies that don't really need fantastic sculpting skills to complete.