I drive a 1989 Volvo DL. I am short on money and so I am going to go and have my oil change at Sears Auto(which only charges 30.00) as compared with the Volvo Dealer that charges 40.00). Is there anything else that needs to get changed besides the oil filter and the oil that I should ask about(like rings or washers)?

Just make sure they put a new washer on the drain plug.

Q.
When was your tranny oil changed last?, or diff oil? Might pay to check. Also-the cheap service may use cheap oil-V require pretty good stuff all the time-so you may end up spending more than you think. V shop labour is expensive, but unless you DIY or supply your own oil, you have little reason to be confident a cheaper job is as good. DIY is not difficult, and a purpose of this forum is, IMO, to help you do it,

Ya, I wish I could. I don't have any tools and I live in an effieceny, so I don't have room for tools. Thanks for the info, I am going to go to the more expensive Vovlo place instead.

No self-respecting mechanic will object to you supplying your own oil, and filter too, but the labour, abt 10min Minimum, is still to be reckoned with. Usually they 'look over' other things too, to generate extra business (by both fair and foul means) if nothing else. Dealer labour is usually more expert/expensive on your marque, but an experienced private mechanic is often much cheaper, and can be better for most things. It's important that your car ISN'T his source of experience at your expense. That can be horrific! All marques have their quirks, and european car servicing is often at a premium price, but not always. Because the car shares many parts/ideologies with other european cars of it's vintage, much of their knowledge car be applied easliy to the V. This is still reasonably true today.

There are no sacred cows, anything one man can assemble another can take apart. You don't HAVE to be a V trained mechanic, but you do have to work slowly and carefully, with a manual or 2 for guides, and a good set of tools. Suitable premises, dexterity, intelligence and physique are a gimme. Time and money then usually become the limiting factors.

BTW> Makers are not usually Gods, and most things can be improved with some ingenuity, tools, time and money. If you do such, document it as fully as possible so when you sell it, some else won't be utterly flabberghasted when having service your modifications and not know where to get parts etc.

It's a pretty good DIY-job

Check: How to change your engine oil