Add paypal link (#243)

Closes #207

Co-authored-by: William Tran <william.tran1@uwaterloo.ca>
Reviewed-on: www/www-new#243
Reviewed-by: Aditya Thakral <a3thakra@csclub.uwaterloo.ca>
Co-authored-by: w25tran <w25tran@localhost>
Co-committed-by: w25tran <w25tran@localhost>

content/get-involved.mdx

@@ -22,7 +22,17 @@ That's all! After your account created, you'll have access to all the
 #### Membership Renewal
 
 If you are already a member of the CSC and want to renew your membership, you
-can do so by coming in person to our office.
+can do so by coming in person to our office. You may also renew your membership 
+online, though you must pay more than the usual $2.00 to cover PayPal fees. 
+A one-term renewal via PayPal comes out to $2.37.
+
+<p>
+  <form action="https://www.paypal.com/cgi-bin/webscr" method="post">
+    <input type="hidden" name="cmd" value="_s-xclick"/>
+    <input type="hidden" name="hosted_button_id" value="9065852"/>
+    <button size="small" name="submit">Renew by PayPal</button>
+  </form>
+</p>
 
 </details>