Will steam summer sale cards get any higher in price?

I think not. In the last few hours people with few cards will rush to sell them for a little profit, so the price will just keep dropping.

last day 3c per card :)

Higher? no way, prices will crash :3

Personally, i reckon they'll be higher. With everyone rushing to complete badges before the cards expire :)

IMO, no, look at price history, at first day, it was 50+ cent, now lol... 10 cent?

Nope, you should have sold in the first few days, when they were 39 cents since everyone was buying like crazy, they will just keep going down in price, they're already 11-12 cents.

they will stay the same within a cent or so until the end of the sale.

They should drop to +- 3cts/card. But that never happens... Instead thousands of cards will be lost at the end of the sale.

if last year is any indicator then no. they just keep getting cheaper and cheaper.

They expire at the end of the sale so I guarantee they will keep dropping until the sale is over.

During the winter they went up in price 1-2 hours before the end of the sale IIRC (probably because everyone expected them to drop in price and postponed making the badge), but this time the situation might be a bit different. I also wouldn't take last year's summer cards situation as an example because last year cards didn't disappear at the end of the sale. We can't know for sure, but don't expect them to skyrocket in price.