On one level, ho ho ho, and I always wonder just how much people offering penetrative sex without condoms know about the risk/reward ratio, but I do go 'argh' at some of that.
So, with apologies for spoiling some of the joke...
(not to mention the fact that they are out of date the day you get them because of the 3 month window period for HIV).
The primary test used in the UK is able to give a positive diagnosis a month after actual infection, and it's this one which should be generally used. It replaces a less sensitive test which needed around six weeks between infection and testing. Both these look for antibodies to HIV.
There is another test which can detect HIV infection earlier still, about a week after infection, because it looks for the virus directly. Partly because it's more expensive, it tends to be used only in situations where it is critical to know as soon after possible infection as possible.
Outside clinics, there are mouth swab and finger prick tests. These need a longer period after infection before they give a positive result, and yes, it's up to three months. Because these also have a significant level of 'false positives' (i.e. they say someone's HIV+ when they are not) they need to have further tests done on anyone with a positive result before a diagnosis is given.
Therefore I would view this as a very high risk activity.
If he's HIV+, they'd be about 1/500 chance of catching it off him (or somewhere between 1/100 and 1/30 if you do anal, and both would be riskier if he caught HIV in the past month or otherwise has a high 'viral load' in his semen).
If I provided you with bareback sex I would be ethically bound not to risk any other gentleman's health by having any kind of sexual contact with him so could not work for 3 months.
Condoms: they're lovely! If you did catch HIV off him, your chances of passing it on via unprotected sex will be higher than the usual 1/1,666 (it's safer to be the one with the penis with sexual transmission) for the first weeks, but using condoms properly cuts that down to nil or very very nearly so.
If I contract HIV I will have a maximum of 20 years to live, meaning I will die by the age of 40, cutting my life expectancy in half.
Again, I recognise where you're coming from in writing this, but this bit makes me go 'argh' in particular. Combination therapy (taking three or more anti-HIV drugs) has absolutely transformed the life expectancy of people with HIV since the mid-90s. Quality of life will be affected - you really do not want to be HIV+ - but you should have no less of it. People who die because of Aids in the UK now typically were never tested for HIV until too late.
And your life expectancy is likely to be rather higher than 40 years, unless you've some very interesting hobbies.
Oh, if anyone else copies this idea, do make sure that weekly rate x 50 is around what you're declaring to the tax authorities and, if you're in the UK, that it falls below the VAT threshold. Otherwise, at some point, someone will forward it to (or actually be from) HMR&C and eyebrows will be raised.