What is the biggest difference in who controls the 401(k) and ira retirement plans?

The biggest difference is that a 401k plan has a limited set of options, as opposed to an IRA plan that has virtually unlimited choices of investment options. The individual has more control over an IRA plan that a 401k plan. In a 401k plan, there is a plan fiduciary and a plan sponsor, whereas an IRA plan has neither.

you will have $2593.74 in 10 years if you set aside $1,000 at 10%

you will have $9321.91 in 20 years if you set aside $2000 at 8%

you will have $1469.32 in 5 years if you set aside $1000 at 8%

you will have $1296.87 in 10 years if you set aside $500 at 10%

you will have $239.66 in 15 years if you set aside $100 at 6%

you will have $4660.96 in 20 years if you set aside $1000 at 8%