Cheap computer for parents.

Honestly, you'll be hard pressed to build a decent machine for less than a budget pre-built one from a company like Dell. If they just want to browse the web and use Word and email, almost any PC will work decently now. Look at something like the 20" Inspiron all-in-one for $449. I'm not sure you could put something together with a 20" monitor, keyboard mouse and OS license etc for that price.

They have a monitor, keyboard, mouse, and OS. I have all ready put together a pentium machine for $325- did not post it but it is easy. For them I thought maybe ITX and thought I would ask you guys for suggestiong.

PCPartPicker part list: http://pcpartpicker.com/p/CugI
Price breakdown by merchant: http://pcpartpicker.com/p/CugI/by_merchant/
Benchmarks: http://pcpartpicker.com/p/CugI/benchmarks/

CPU: Intel Pentium G860 3.0GHz Dual-Core Processor ($68.76 @ Amazon)
Motherboard: ASRock H61M-DGS Micro ATX LGA1155 Motherboard ($44.99 @ Amazon)
Memory: Mushkin Essentials 4GB (2 x 2GB) DDR3-1333 Memory ($23.98 @ Outlet PC)
Storage: Western Digital Caviar Blue 500GB 3.5" 7200RPM Internal Hard Drive ($49.98 @ Outlet PC)
Case: Thermaltake VL80001W2Z ATX Mid Tower Case ($29.99 @ Newegg)
Power Supply: Antec Basiq 350W ATX12V Power Supply ($29.99 @ Amazon)
Optical Drive: Samsung SH-224BB DVD/CD Writer ($15.98 @ Outlet PC)
Total: $263.67
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-02-09 18:24 EST-0500)

Awesome! But what about an ITX build?

itx your going to pay a few more $$ for a slightly smaller case. also a lot of atx cases use laptop bricks and small power supplys. your better off picking up a stock mini atx case and stock power supply. if the ps dies they can replace it with a stock atx power supply.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
http://www.microcenter.com/product/408966/Pentium_G2020...
your better off picking up a x7x mb if the cpu cant handle there use in a few years you may be able to drop in a 4 cord ib for cheap. the ib chip is made for small system it max wattage is 55w. so it going to run cool. the best bang for the bucks for the system is adding extra ram.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
the cpu and mb combo give you better gpu then the intel cpu at the same price if they watch you tube videos or dvd movies.

PCPartPicker part list: http://pcpartpicker.com/p/CyVJ
Price breakdown by merchant: http://pcpartpicker.com/p/CyVJ/by_merchant/
Benchmarks: http://pcpartpicker.com/p/CyVJ/benchmarks/

Motherboard: ASRock E350M1/USB3 Mini ITX E-Series E-Series E-350 Motherboard ($99.99 @ Newegg)
Memory: Corsair Vengeance 4GB (1 x 4GB) DDR3-1600 Memory ($26.99 @ Newegg)
Storage: Western Digital Caviar Blue 500GB 3.5" 7200RPM Internal Hard Drive ($49.98 @ Outlet PC)
Case: Cooler Master Elite 120 Advanced (Black) Mini ITX Tower Case ($39.99 @ Amazon)
Power Supply: Corsair Builder 430W 80 PLUS Bronze Certified ATX12V Power Supply ($34.99 @ Newegg)
Optical Drive: Samsung SH-224BB DVD/CD Writer ($15.98 @ Outlet PC)
Total: $267.92
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-02-10 01:04 EST-0500)