I only see what you have told me. sure would be nice to 1 go inside, and 2 be with a specialists in foundations.
But, 1, every home needs to be on its own hill that sheds water away and off the grounds around the foundation. This can be done by you and takes very little work and some money. I see this as not a big problem. Gutters, downspouts, sheathing, rocks, sand, finish dirt, then packing and packing and watering and packing.
Now, the front porch. Most front and back porches in my region are poured individually so that they move on their own accord and do not drag down the home or the side of a home. Apparently your porches are attached. Now, some buiders, do a good job on foundation prep on the proper home, but skimp on the porches. You seem to need the porch jacked back up to level and that will take the stress off the foundation and the walls. So, in my region, a jack costs $600 and one is needed every 8 feet. This is for a home proper, so your porch may not need that many and may definately not need to go as deep as for the homes foundation. So, I think without seeing the situation, think that you can do this way under your thinking outloud budget.
You have other issues that foundation slipping can cause that you cannot see because of no access to interior and to the inside walls. If this slipping is too drastic, you could have busted water lines, broken electric lines, and other "inside" issues that you will not know until you charge the lines. No one will know this.
There is nothing worse than buying a home saving some money and fint out that its a living hell. But its your gamble. Then 12 years old is not old for a home. Its really young, but some people can tear a home up in 1/12 of that time, but most of that is cosmetic. severe internal damage is pretty remote.
Will not give my opinion or what I would do, because I do not. I do not have enough information and actually you do not either.