RBC pays 0% interest on DI accounts. Currently they pay 0.55% interest on savings accounts, a bit better place to stash it until you make a stock purchase, typically hold in savings and then transfer the lump sum over (plus interest).
Tangerine savings accounts pay 0.80%, slightly better. The TFSA GIC within the tangerine TFSA is even better for cash, 1 year GIC is 1.40%. I have used Tangerine to start out, I found the act of moving the money into a second (free) bank encouraged stronger savings. PC financial is pretty much the same, I like the tangerine sign up bonus.
TFSA is better than RSP for small amounts of money. The clawbacks you get, from an RRSP account, when its a smaller amount will destroy any tax benefits you get now. Without knowing your details, its a general rule that anyone earning less than $45k should stick to TFSA until its maxed. With more details we could optimize your savings, given that its slightly different in Canada.
My Orange key, if you think I've been helpful, is: 16794736S1 Feel free to message me for clarification, I understand the desire to get savings when you have debt, I was $35K in debt when I opened my ING account (ING sold out to become Tangerine).