Reddit reviews 28 Pieces 120 to 3000 Grit Wet Dry Sandpaper Assortment Abrasive Paper Sheets 9 by 3.6 Inches for Automotive Sanding, Wood Furniture Finishing, Wood Turing Finishing

I used this pack.
https://www.amazon.com/dp/B01MZALAD9/ref=cm_sw_r_cp_apip_eFlQOZv7B25tE

I believe I started with a course grit around 400ish, and went all the way down to 3000

This build will be able to play anything at 1080p 60fps high settings:

PCPartPicker part list / Price breakdown by merchant

Type|Item|Price
:----|:----|:----
CPU | Intel - Pentium G4560 3.5GHz Dual-Core Processor | $79.44 @ OutletPC
Motherboard | MSI - B250M PRO-VD Micro ATX LGA1151 Motherboard | $54.89 @ OutletPC
Memory | G.Skill - Ripjaws V Series 8GB (1 x 8GB) DDR4-2800 Memory | $65.99 @ Newegg
Storage | Crucial - MX300 275GB 2.5" Solid State Drive | $97.88 @ OutletPC
Video Card | Gigabyte - GeForce GTX 1060 3GB 3GB Windforce OC Video Card | $216.89 @ SuperBiiz
Case | Fractal Design - Focus G (White) ATX Mid Tower Case | $44.99 @ Newegg
Power Supply | EVGA - 450W 80+ Bronze Certified ATX Power Supply | $34.97 @ Amazon
| Prices include shipping, taxes, rebates, and discounts |
| Total (before mail-in rebates) | $605.05
| Mail-in rebates | -$10.00
| Total | $595.05
| Generated by PCPartPicker 2017-08-07 00:58 EDT-0400 |

If you want 4k 60fps high settings, you're going to have to significantly increase your budget:

PCPartPicker part list / Price breakdown by merchant

Type|Item|Price
:----|:----|:----
CPU | AMD - Ryzen 5 1600 3.2GHz 6-Core Processor | $197.88 @ OutletPC
Motherboard | ASRock - AB350M Micro ATX AM4 Motherboard | $59.99 @ Newegg
Memory | G.Skill - Ripjaws V Series 16GB (2 x 8GB) DDR4-3000 Memory | $124.99 @ Newegg
Storage | Crucial - MX300 275GB 2.5" Solid State Drive | $97.88 @ OutletPC
Video Card | Gigabyte - GeForce GTX 1080 8GB WINDFORCE OC 8G Video Card | $514.98 @ Newegg
Case | Fractal Design - Define Mini C with Window MicroATX Mid Tower Case | $69.99 @ Newegg
Power Supply | EVGA - SuperNOVA G2 550W 80+ Gold Certified Fully-Modular ATX Power Supply | $72.98 @ Newegg
| Prices include shipping, taxes, rebates, and discounts |
| Total (before mail-in rebates) | $1148.69
| Mail-in rebates | -$10.00
| Total | $1138.69
| Generated by PCPartPicker 2017-08-07 01:01 EDT-0400 |

Edit: Here is the stuff you'll need to paint your case orange:

https://www.amazon.com/Sandpaper-Assortment-Automotive-Furniture-Finishing/dp/B01MZALAD9/ref=sr_1_5?ie=UTF8&qid=1502082191&sr=8-5&keywords=sandpaper

https://www.amazon.com/Rust-Oleum-280715-Primer-American-Accents/dp/B00KZ6LLZW/ref=sr_1_1?s=hi&ie=UTF8&qid=1502082223&sr=1-1&keywords=white+primer+spray+paint

https://www.amazon.com/280698-American-Accents-Orange-12-Ounce/dp/B00KZ6LVUW/ref=sr_1_2?s=hi&ie=UTF8&qid=1502082246&sr=1-2&keywords=orange+spray+paint

https://www.amazon.com/Oleum-280702-American-Accents-12-Ounce/dp/B00KZ6LYMM/ref=sr_1_1?s=hi&ie=UTF8&qid=1502082271&sr=1-1&keywords=spray+paint+gloss+finish