Well according to the e-mails and posters I've been getting, Welcome Day seems to be free except for the cost of parking ($5.00) and lunch. You can also do that "stay in residence" thing which is $75 and $50 for a double and single room per night, respectively.
Apart from that, the events are:
David Braley Athletic Centre and Ivor Wynne Centre (Athletic Complex) (Tours 9am - 1:30pm)
Residence Hall Tours (Tours 9am - 3pm) Meet at the lobby of desired residence for tour!
Totally Transit Tours (Tours 1pm - 3pm, every 15 minutes)
Debunking the Myths: Student Panel (Hamilton Hall 109, 10am - 11am and 1pm - 2pm)
First Year Parent Program (Burke Science Building B136, 10am - 11am and 1pm - 2pm)
Living Off-Campus (Michael DeGroote Centre for Learning & Development 1105, 10am - 11am and 1pm-2pm)
Your Home Away From Home (Chester New Hall 104, 10am - 11am and 1pm-2pm)
Information Fair (9am - 3pm, MUSC Marketplace)
Taking Effective Study Notes. Dr. Day (CIBC Hall in the Student Centre, 10am - 11pm and 1pm-2pm)
First Generation Program (CIBC Hall, 12pm - 1pm)
Finances Matters! Financial Aid and Managing your Student Account (Burke Science Building 106, 10am - 11pm and 1pm - 2pm)
I believe these are tours/lectures that help you get more accustomed to university.
Oh you can also buy your MacPass on Welcome Day too so. xP
Hope this helped though I'm just repeating the email.
