OK, I'll be happy to help you out as I do this all day long (and have for the last 13 years). There are three "variables" that determine whether you will get a mortgage or not: Credit, Assets, and Income. There are also two basic types of loans out there:
Conventional: FNMA (aka Fannie Mae) and FHLMC (aka Freddie Mac) and
Government:FHA and VA. Since I personally can't stand dealing with government loans (think of a bank run with all of the government red tape), I will only be addressing conventional loans.
Credit: When you say "very little" credit, what do you mean? Most loans are usually underwritten to FNMA and FHLMC guidelines as they are the ultimate "purchasers" of most mortgages (~75%). Both agencies require a
minimum of three credit references to obtain financing. Obviously most revolving credit cards are acceptable sources of credit, as well as any installment loans(ie school, auto, personal, etc.). But there are other "alternative" means of credit. Do you have any utilities in your name? Cable, telephone or even an ISP works. I have even gotten references from auto insurance companies and child care providers. If you can prove (either by a letter or cancelled checks, etc.)that you have made timely payments (no payments over 30 days late) then this will usually work. I cannot tell you how many loans I have done using this type of documentation. One or two 30 day lates isn't the end of world, but if you only have three credit items and two of them have late payments then you may have problems...
Assets Just about everyone can get away with putting 5% down these days. The only problem with putting less than 20% down is that you must insure the loan against default if you put less than 20% down. This insurance is called PMI (Private Mortgage Insurance) and with 5% down adds approximately .75% to your interest rate(before you complain, prior to the advent of PMI you had to put at least 20% down to buy a house)! So you decide whether you want to give your money to your landlord while you try to save 20% or bite the bullet and get PMI. There are some ways to avoid PMI, and some programs with 0-3% down, but I'm trying to keep this simple. You should also note that the 5% you are putting down, must be your own money (ie in YOUR bank account for at least 60-90 days). There is an exception to this rule though: If you put at least 20% down then the entire amount can be a gift from a blood relative.
Income: This is a little more tricky because there are a couple of variables that I don't know. How much are the property taxes per month/year? I have taken a wild guess of
$100 per month. Insurance where I live is (very roughly) $400 per year, but that is on a house worth anywhere from $200,000 - $400,000. Insurance covers more than rebuilding the house if it is destroyed. It covers liability of other people on your property, theft, etc. In your case I have used a figure of $240 (based on a complete guess)per year (
$20 per month) until you check with an insurance agent. You also mentioned that you don't have too much other debt so I will assume a figure of
$50 per month. This "other" debt
includes revolving charge cards, installment loans, student loans that are due within one year, loans taken out against your retirement plan that show up as a deduction on your paycheck, alimony/child, etc. etc. etc. This "other" debt
does not include installment loans with less than 10 payments left, utilities, daycare or a loan from your parents, friend, or any other "non-credit" reporting company that you forgot about

.
Calculation Time:Your monthly debts including the mortgage principle and interest (called
P&I), property taxes, homeowners insurance, private mortgage insurance (
PMI) and other monthly debts can be approximately
40% of your
gross income. In your example you stated that you made ~$20,000 per year or $1667 per month. Multiplying that amount ($1667) X 40% equals
$667 per month. Now you must subtract the taxes ($100) insurance ($20) and the "other" debt ($50). This leaves you with $497 for the P&I and the PMI. Allowing .75% for the PMI, you could qualify for a mortgage of
$65,000 at a rate of
7.25% for 30 years. This would require a downpayment of
$3421. The total payment for the house would be
$605.66 (PMI isn't "exactly" .75%, it's less) and your other debt would be $50. $655 divided by your monthly income equals 39% so it checks out. Increasing the rate to
7.5% only changes the payment to $616.74 so there is no need to panic if rates go up a little (most of my clients contemplate suicide before they find this out). You can also extrapolate up (or down) allowing approx. $9 per quarter percent change. As far as the loan amount is concerned, borrowing $1000 at 7.25% equals
$7.47 (including the PMI) so if you want to calculate how much a mortgage of $30,000 would be (assuming taxes and insurance remain the same), just multiply 30 X $7.47 which equals $224.10. Add to that the taxes and insurance figure of $120 and your mortgage payment would be
$344.
Obviously there are certain items I have missed and, as someone else had mentioned, your utilities and other monthly expenses should be taken into consideration. Hopefully this gives you a rough idea of where to start. Unfortunately I won't be able to respond to any questions or other scenarios that this may have raised until later tomorrow, but I doubt that you will be attempting to buy a house tomorrow...this morning! Feel free to email me with any questions that you may have that you don't feel like posting here.
EDIT: I just noticed that you live in Canada and since these are American "rules" I'm not sure if they will help you out. Maybe someone can use this information.
