Congratulations brother Bear you have done well!!!!! Brother ABFer and Von have given you some good advice and I would like to contribute some ideas myself. You have nothing to loose and everything to gain by joining the ABF credit union. The 401k is another story. If you do not feel comfortable managing your own money and you don't think you will be able save on your own, your best bet is to join the 401k. But ABF does not contribute or match any money you put into the 401k. You will have more control if you open and contribute to an IRA. But a Traditional IRA is more responsibility and you can only contribute about half of what you can put into a 401k. The fees associated with an IRA are usually less than with a 401k and the return for the same funds are usually higher because of the fees. The 401k will not let you trade like an IRA so you have less chance of loosing your money but also less chance of making a higher rate of return. And finally, unless you leave ABF you will not have access to your 401k money but an IRA will allow you to withdraw all of your money at anytime as long as you are willing to pay an additional 10% PENALTY.
Personally, I would suggest having both a 401k and a traditional IRA. Contribute about $25 a week to both and see which you like best, then decide what you want to do. Good luck brother Bear you are off to a good start!