The best bet to keep costs down is to leave your plumbing where it is. So you won't be appreciably moving the fixtures.

First, find out what's in the wall where you'd like to move the door. Then find out why the shower is 3.5" lower than the rest of the floor. Once you know those 2 things, you'll have some idea of what is possible. Then you need to decide what the main use for this bathroom is. If it's basically a powder room that happens to have a shower, your approach will be different from what it would be for a full-use bathroom.

For a full-use bath, this is what I'd do:

• if possible, move the door over
• consider boxing in the ceiling pipes
• if possible, raise the shower floor
• get rid of the framed, glass shower door. Consider replacing either with a curtain (inexpensive and easy to clean) or a an unframed glass shower enclosure (expensive)
• do the entire floor including shower in the same tile
• decide if there is room for a vanity instead of a wall sink. If not, determine where other storage space can be created
• add more and better lighting
• add an exhaust fan

Remove shower enclosure …base boards…and all the tile…level the floor…then pick an inexpensive ..a relatively small mosaics would be easiest to fit the odd angles…to use on the floor ….then tile the shower walls and the strip of wall behind the sink…..with a slightly larger tile…

install a curved shower curtain rod…and add a ledge shelf deep enough and high enough for shampoos,soaps,etc… at the other end of the shower ….some shallow shelving above the toilet….find pretty baskets for bathroom necessities..and at the right height…leaving some open spaces in shelving for art or decor…ignore the pipes..even explore a more industrial decor/color theme if that appeals to you…this will allow-a simple or even an old but interesting mirror at the entry rather than a protruding mirror