As said above, doesn't look good.
The cheapest and easiest option would be to buy a good known bottom end or full engine.

But if you want to rebuild it, DIY as liam said can vary depending on machining needed.
As a rough guesstimate, my build with arp rod bolts and crank & flywheel grind and skim probably cost between about £400 and £500. That's just a quick sum if all the main parts off the top of my head.

Hope you get it sorted though bud...and get it set up properly after too! Lol