Sleeping is cheaper way to restore life or mana compared to drinking potions. Do this often, especially after a tough fight. You can use a bed or straw, by teleporting to it, sleeping, and teleporting back. However, there is a easier way. The trick involves the method used to create a straw bed (unfolding the first straw bunch, then moving a second one into it) at the ground. However, this also works in your inventory. You can have a bed anywhere and at any time. Keep in mind that this method has two downsides: the weight of the straw and the inability to move unfolded straw into your inventory. The solution for these downsides is the real portable bed. Normally a bed is unmovable, but there is a at least one bed, which is movable. You can move it into your inventory (and out and back in again as desired). This particular bed, which looks exactly like the usual beds, is weightless. To find it, go to the lonely house between the cursed abbey and the church (both are north of the farmland), directly next to the river. To get inside the house, you need level 1 Lock Pick skill.